c++常用算法模板
SPFA单源最短路模板
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int inf=0x3f3f3f3f;
const int N=114514;
const LL INF = (1LL<<31)-1;
int d[N],n,m,s;
bool in_queue[N];
queue<int> q;
struct node{
int w,v;
node(){}
node(int vv,int ww){
v=vv;
w=ww;
}
};
vector<node> g[N];
void spfa(int s){
memset(in_queue,0,sizeof(in_queue));
for(int i=1; i<=n; ++i)
d[i] = INF;
d[s]=0;
in_queue[s]=1;
q.push(s);
while(!q.empty()){
int v=q.front();
q.pop();
in_queue[v]=0;
for(int i=0;i<g[v].size();i++){
int x=g[v][i].v;
if(d[x]>d[v]+g[v][i].w){
d[x]=d[v]+g[v][i].w;
if(!in_queue[x]){
q.push(x);
in_queue[x]=1;
}
}
}
}
}
int main(){
cin>>n>>m>>s;
for(int i=0;i<m;i++){
int u,v,w;
cin>>u>>v>>w;
g[u].push_back(node(v,w));
g[u].push_back(node(u,w));
}
spfa(s);
for(int i=1;i<=n;i++){
cout<<d[i]<<" ";
}
}
快读快写模板
inline int read(){
int f=1,s=0;char c=getchar();
while(c<'0'||c>'9'){
if(c=='-') f=-1;c=getchar();
}
while(c>='0'&&c<='9'){
s=s*10+c-'0';c=getchar();
}
return f*s;
}
inline void print(int x){
if(x<0){
putchar('-');print(-x);return;
}
if(x>9)
print(x/10);
putchar(x%10+'0');
}
Dijkstra单源最短路模板
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int maxn = 1e5+10;
const int maxm = 2e5+10;
const int INF = (1<<31)-1;
int head[maxm], vis[maxn];
LL dix[maxn];
int n, m, s, tot=0;
struct node {
int to, nxt, d;
} edge[maxm];
struct Point {
int dd, p;
bool operator <(const Point &x) const {
return dd > x.dd;
}
} ;
void add(int x, int y, int z) {
edge[tot].to = y;
edge[tot].d = z;
edge[tot].nxt = head[x];
head[x] = tot++;
}
void dijkstra() {
for(int i=1; i<=n; ++i)
dix[i] = INF;
memset(vis, 0 ,sizeof(vis));
dix[s] = 0;
priority_queue<Point> que;
Point a;
a.dd = 0;
a.p = s;
que.push(a);
while(que.size()) {
a = que.top();
que.pop();
int x = a.p;
if(vis[x]) continue;
vis[x] = 1;
for(int i=head[x]; i!=-1; i=edge[i].nxt) {
int y = edge[i].to;
if(dix[y] > dix[x] + 1LL*edge[i].d) {
dix[y] = dix[x] + 1LL * edge[i].d;
a.dd = dix[y];
a.p = y;
que.push(a);
}
}
}
}
int main() {
scanf("%d%d%d", &n, &m, &s);
memset(head, -1, sizeof(head));
while(m--) {
int x, y, z;
scanf("%d%d%d", &x, &y, &z);
add(x, y, z);
}
dijkstra();
for(int i=1; i<n; ++i)
printf("%lld ", dix[i]);
printf("%lld\n", dix[n]);
return 0;
}
floyd多源最短路模板
#include<bits/stdc++.h>
using namespace std;
int d[110][110],n,m,u,v,w;
void floyd(){
for(int i=1;i<=n;i++)d[i][i]=0;
for(int k=1; k<=n; k++)
for(int i=1; i<=n; i++)
for(int j=1; j<=n; j++)
d[i][j]=min(d[i][j],d[i][k]+d[k][j]);
}
int main() {
memset(d,0x3f,sizeof(d));
cin>>n>>m;
for(int i=1; i<=m; i++){
cin>>u>>v>>w;
d[u][v]=w;
d[v][u]=w;
}
floyd();
for(int i=1; i<=n; i++) {
for(int j=1; j<=n; j++)
cout<<d[i][j]<<" ";
cout<<endl;
}
return 0;
}
高精度加法模板
#include<bits/stdc++.h>
using namespace std;
const int L=110;
string add(string a,string b)
{
string ans;
int na[L]={0},nb[L]={0};
int la=a.size(),lb=b.size();
for(int i=0;i<la;i++) na[la-1-i]=a[i]-'0';
for(int i=0;i<lb;i++) nb[lb-1-i]=b[i]-'0';
int lmax=la>lb?la:lb;
for(int i=0;i<lmax;i++) na[i]+=nb[i],na[i+1]+=na[i]/10,na[i]%=10;
if(na[lmax]) lmax++;
for(int i=lmax-1;i>=0;i--) ans+=na[i]+'0';
return ans;
}
int main()
{
string a,b;
cin>>a>>b；
cout<<add(a,b)<<endl;
return 0;
}
高精度减法模板
#include<bits/stdc++.h>
using namespace std;
const int L=110;
string sub(string a,string b)
{
string ans;
int na[L]={0},nb[L]={0};
int la=a.size(),lb=b.size();
for(int i=0;i<la;i++) na[la-1-i]=a[i]-'0';
for(int i=0;i<lb;i++) nb[lb-1-i]=b[i]-'0';
int lmax=la>lb?la:lb;
for(int i=0;i<lmax;i++)
{
na[i]-=nb[i];
if(na[i]<0) na[i]+=10,na[i+1]--;
}
while(!na[--lmax]&&lmax>0) ;lmax++;
for(int i=lmax-1;i>=0;i--) ans+=na[i]+'0';
return ans;
}
int main()
{
string a,b;
cin>>a>>b;
cout<<sub(a,b)<<endl;
return 0;
}
高精度乘法模板
#include<bits/stdc++.h>
using namespace std;
const int L=110;
string mul(string a,string b) {
string s;
int na[L],nb[L],nc[L],La=a.size(),Lb=b.size();
fill(na,na+L,0);
fill(nb,nb+L,0);
fill(nc,nc+L,0);
for(int i=La-1; i>=0; i--) na[La-i]=a[i]-'0';
for(int i=Lb-1; i>=0; i--) nb[Lb-i]=b[i]-'0';
for(int i=1; i<=La; i++)
for(int j=1; j<=Lb; j++)
nc[i+j-1]+=na[i]*nb[j];
for(int i=1; i<=La+Lb; i++)
nc[i+1]+=nc[i]/10,nc[i]%=10;
if(nc[La+Lb]) s+=nc[La+Lb]+'0';
for(int i=La+Lb-1; i>=1; i--)
s+=nc[i]+'0';
return s;
}
int main() {
string a,b;
cin>>a>>b;
cout<<mul(a,b)<<endl;
return 0;
}
高精度除法/取余模板
#include<bits/stdc++.h>
using namespace std;
const int L=110;
int sub(int *a,int *b,int La,int Lb) {
if(La<Lb) return -1;
if(La==Lb) {
for(int i=La-1; i>=0; i--)
if(a[i]>b[i]) break;
else if(a[i]<b[i]) return -1;
}
for(int i=0; i<La; i++) {
a[i]-=b[i];
if(a[i]<0) a[i]+=10,a[i+1]--;
}
for(int i=La-1; i>=0; i--)
if(a[i]) return i+1;
return 0;
}
string div(string n1,string n2,int nn) {
string s,v;
int a[L],b[L],r[L],La=n1.size(),Lb=n2.size(),i,tp=La;
fill(a,a+L,0);
fill(b,b+L,0);
fill(r,r+L,0);
for(i=La-1; i>=0; i--) a[La-1-i]=n1[i]-'0';
for(i=Lb-1; i>=0; i--) b[Lb-1-i]=n2[i]-'0';
if(La<Lb || (La==Lb && n1<n2)) {
return n1;
}
int t=La-Lb;
for(int i=La-1; i>=0; i--)
if(i>=t) b[i]=b[i-t];
else b[i]=0;
Lb=La;
for(int j=0; j<=t; j++) {
int temp;
while((temp=sub(a,b+j,La,Lb-j))>=0) {
La=temp;
r[t-j]++;
}
}
for(i=0; i<L-10; i++) r[i+1]+=r[i]/10,r[i]%=10;
while(!r[i]) i--;
while(i>=0) s+=r[i--]+'0';
i=tp;
while(!a[i]) i--;
while(i>=0) v+=a[i--]+'0';
if(v.empty()) v="0";
if(nn==1) return s;
if(nn==2) return v;
}
int main() {
string a,b;
cin>>a>>b;
cout<<div(a,b,1)<<endl;
return 0;
}
高精度阶乘模板
#include<bits/stdc++.h>
using namespace std;
const int L=100005;
int a[L];
string fac(int n) {
string ans;
if(n==0) return "1";
fill(a,a+L,0);
int s=0,m=n;
while(m) a[++s]=m%10,m/=10;
for(int i=n-1; i>=2; i--) {
int w=0;
for(int j=1; j<=s; j++) a[j]=a[j]*i+w,w=a[j]/10,a[j]=a[j]%10;
while(w) a[++s]=w%10,w/=10;
}
while(!a[s]) s--;
while(s>=1) ans+=a[s--]+'0';
return ans;
}
int main() {
int n;
cin>>n;
cout<<fac(n)<<endl;
return 0;
}
高精度幂模板
#include<bits/stdc++.h>
using namespace std;
#define L(x) (1 << (x))
const double PI = acos(-1.0);
const int Maxn = 133015;
double ax[Maxn], ay[Maxn], bx[Maxn], by[Maxn];
char sa[Maxn/2],sb[Maxn/2];
int sum[Maxn];
int x1[Maxn],x2[Maxn];
int revv(int x, int bits) {
int ret = 0;
for (int i = 0; i < bits; i++) {
ret <<= 1;
ret |= x & 1;
x >>= 1;
}
return ret;
}
void fft(double * a, double * b, int n, bool rev) {
int bits = 0;
while (1 << bits < n) ++bits;
for (int i = 0; i < n; i++) {
int j = revv(i, bits);
if (i < j)
swap(a[i], a[j]), swap(b[i], b[j]);
}
for (int len = 2; len <= n; len <<= 1) {
int half = len >> 1;
double wmx = cos(2 * PI / len), wmy = sin(2 * PI / len);
if (rev) wmy = -wmy;
for (int i = 0; i < n; i += len) {
double wx = 1, wy = 0;
for (int j = 0; j < half; j++) {
double cx = a[i + j], cy = b[i + j];
double dx = a[i + j + half], dy = b[i + j + half];
double ex = dx * wx - dy * wy, ey = dx * wy + dy * wx;
a[i + j] = cx + ex, b[i + j] = cy + ey;
a[i + j + half] = cx - ex, b[i + j + half] = cy - ey;
double wnx = wx * wmx - wy * wmy, wny = wx * wmy + wy * wmx;
wx = wnx, wy = wny;
}
}
}
if (rev) {
for (int i = 0; i < n; i++)
a[i] /= n, b[i] /= n;
}
}
int solve(int a[],int na,int b[],int nb,int ans[]) {
int len = max(na, nb), ln;
for(ln=0; L(ln)<len; ++ln);
len=L(++ln);
for (int i = 0; i < len ; ++i) {
if (i >= na) ax[i] = 0, ay[i] =0;
else ax[i] = a[i], ay[i] = 0;
}
fft(ax, ay, len, 0);
for (int i = 0; i < len; ++i) {
if (i >= nb) bx[i] = 0, by[i] = 0;
else bx[i] = b[i], by[i] = 0;
}
fft(bx, by, len, 0);
for (int i = 0; i < len; ++i) {
double cx = ax[i] * bx[i] - ay[i] * by[i];
double cy = ax[i] * by[i] + ay[i] * bx[i];
ax[i] = cx, ay[i] = cy;
}
fft(ax, ay, len, 1);
for (int i = 0; i < len; ++i)
ans[i] = (int)(ax[i] + 0.5);
return len;
}
string mul(string sa,string sb) {
int l1,l2,l;
int i;
string ans;
memset(sum, 0, sizeof(sum));
l1 = sa.size();
l2 = sb.size();
for(i = 0; i < l1; i++)
x1[i] = sa[l1 - i - 1]-'0';
for(i = 0; i < l2; i++)
x2[i] = sb[l2-i-1]-'0';
l = solve(x1, l1, x2, l2, sum);
for(i = 0; i<l || sum[i] >= 10; i++) {
sum[i + 1] += sum[i] / 10;
sum[i] %= 10;
}
l = i;
while(sum[l] <= 0 && l>0) l--;
for(i = l; i >= 0; i--) ans+=sum[i] + '0';
return ans;
}
string Pow(string a,int n) {
if(n==1) return a;
if(n&1) return mul(Pow(a,n-1),a);
string ans=Pow(a,n/2);
return mul(ans,ans);
}
int main() {
cin.sync_with_stdio(false);
string a;
int b;
cin>>a>>b;
cout<<Pow(a,b)<<endl;
return 0;
}
高精度进制转换模板
#include<iostream>
#include<algorithm>
using namespace std;
bool judge(string s) {
for(int i=0; i<s.size(); i++)
if(s[i]!='0') return 1;
return 0;
}
string solve(string s,int n,int m) {
string r,ans;
int d=0;
if(!judge(s)) return "0";
while(judge(s)) {
for(int i=0; i<s.size(); i++) {
r+=(d*n+s[i]-'0')/m+'0';
d=(d*n+(s[i]-'0'))%m;
}
s=r;
r="";
ans+=d+'0';
d=0;
}
reverse(ans.begin(),ans.end());
return ans;
}
int main() {
string s;
int n,m;
cin>>s>>n>>m;
cout<<solve(s,n,m)<<endl;
return 0;
}
高精度平方根模板
#include<bits/stdc++.h>
using namespace std;
const int L=2015;
string add(string a,string b) {
string ans;
int na[L]= {0},nb[L]= {0};
int la=a.size(),lb=b.size();
for(int i=0; i<la; i++) na[la-1-i]=a[i]-'0';
for(int i=0; i<lb; i++) nb[lb-1-i]=b[i]-'0';
int lmax=la>lb?la:lb;
for(int i=0; i<lmax; i++) na[i]+=nb[i],na[i+1]+=na[i]/10,na[i]%=10;
if(na[lmax]) lmax++;
for(int i=lmax-1; i>=0; i--) ans+=na[i]+'0';
return ans;
}
string sub(string a,string b) {
string ans;
int na[L]= {0},nb[L]= {0};
int la=a.size(),lb=b.size();
for(int i=0; i<la; i++) na[la-1-i]=a[i]-'0';
for(int i=0; i<lb; i++) nb[lb-1-i]=b[i]-'0';
int lmax=la>lb?la:lb;
for(int i=0; i<lmax; i++) {
na[i]-=nb[i];
if(na[i]<0) na[i]+=10,na[i+1]--;
}
while(!na[--lmax]&&lmax>0) ;
lmax++;
for(int i=lmax-1; i>=0; i--) ans+=na[i]+'0';
return ans;
}
string mul(string a,string b) {
string s;
int na[L],nb[L],nc[L],La=a.size(),Lb=b.size();
fill(na,na+L,0);
fill(nb,nb+L,0);
fill(nc,nc+L,0);
for(int i=La-1; i>=0; i--) na[La-i]=a[i]-'0';
for(int i=Lb-1; i>=0; i--) nb[Lb-i]=b[i]-'0';
for(int i=1; i<=La; i++)
for(int j=1; j<=Lb; j++)
nc[i+j-1]+=na[i]*nb[j];
for(int i=1; i<=La+Lb; i++)
nc[i+1]+=nc[i]/10,nc[i]%=10;
if(nc[La+Lb]) s+=nc[La+Lb]+'0';
for(int i=La+Lb-1; i>=1; i--)
s+=nc[i]+'0';
return s;
}
int sub(int *a,int *b,int La,int Lb) {
if(La<Lb) return -1;
if(La==Lb) {
for(int i=La-1; i>=0; i--)
if(a[i]>b[i]) break;
else if(a[i]<b[i]) return -1;
}
for(int i=0; i<La; i++) {
a[i]-=b[i];
if(a[i]<0) a[i]+=10,a[i+1]--;
}
for(int i=La-1; i>=0; i--)
if(a[i]) return i+1;
return 0;
}
string div(string n1,string n2,int nn) {
string s,v;
int a[L],b[L],r[L],La=n1.size(),Lb=n2.size(),i,tp=La;
fill(a,a+L,0);
fill(b,b+L,0);
fill(r,r+L,0);
for(i=La-1; i>=0; i--) a[La-1-i]=n1[i]-'0';
for(i=Lb-1; i>=0; i--) b[Lb-1-i]=n2[i]-'0';
if(La<Lb || (La==Lb && n1<n2)) {
return n1;
}
int t=La-Lb;
for(int i=La-1; i>=0; i--)
if(i>=t) b[i]=b[i-t];
else b[i]=0;
Lb=La;
for(int j=0; j<=t; j++) {
int temp;
while((temp=sub(a,b+j,La,Lb-j))>=0) {
La=temp;
r[t-j]++;
}
}
for(i=0; i<L-10; i++) r[i+1]+=r[i]/10,r[i]%=10;
while(!r[i]) i--;
while(i>=0) s+=r[i--]+'0';
i=tp;
while(!a[i]) i--;
while(i>=0) v+=a[i--]+'0';
if(v.empty()) v="0";
if(nn==1) return s;
if(nn==2) return v;
}
bool cmp(string a,string b) {
if(a.size()<b.size()) return 1;
if(a.size()==b.size()&&a<=b) return 1;
return 0;
}
string BigInterSqrt(string n) {
string l="1",r=n,mid,ans;
while(cmp(l,r)) {
mid=div(add(l,r),"2",1);
if(cmp(mul(mid,mid),n)) ans=mid,l=add(mid,"1");
else r=sub(mid,"1");
}
return ans;
}
string DeletePreZero(string s) {
int i;
for(i=0; i<s.size(); i++)
if(s[i]!='0') break;
return s.substr(i);
}
int main() {
string n;
int t;
cin>>n;
n=DeletePreZero(n);
cout<<BigInterSqrt(n)<<endl;
return 0;
}
最小生成树模板
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int n,m;
const int N = 510;
const int INF = 0x3f3f3f3f;
int g[N][N],dist[N];
bool st[N];
int prim() {
int res = 0;
memset(dist,0x3f,sizeof(dist));
for(int i=0; i<n; i++) {
int t = -1;
for(int j=1; j<=n; j++) {
if(!st[j] && (t == -1 || dist[t] > dist[j])) {
t = j;
}
}
if(i && dist[t] == INF) {
return INF;
}
st[t] = true;
if(i) {
res += dist[t];
}
for(int j=1; j<=n; j++) {
dist[j] = min(dist[j],g[t][j]);
}
}
return res;
}
int main() {
memset(g,0x3f,sizeof(g));
scanf("%d%d",&n,&m);
for(int i=1; i<=m; i++) {
int u,v,w;
scanf("%d%d%d",&u,&v,&w);
g[u][v] = g[v][u] = min(g[u][v],w);
}
int res = prim();
if(res == INF) {
printf("impossible");
} else {
printf("%d",res);
}
return 0;
}
完结撒花！！！
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