A.查找
Key:二分-二分查找
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 1e6+10, MAX = 1e9, INF = -1e9;
int n;
int a[N];
int q;
int x;
void solve(){
cin>>n>>q;
for(int i=1;i<=n;i++)cin>>a[i];
while(q--){
cin>>x;
int l=1;int r=n;
while(l<r){
int mid=(l+r)>>1;
if(a[mid]>=x)r=mid;
else l=mid+1;
}
cout<<((a[l]==x) ? l : -1)<<" ";
}
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
B.跳石头
Key:二分-二分答案
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 2e5+10, MAX = 1e9, INF = -1e9;
int len,n,m;
int a[N];
bool check(int mid){
int num=0;
int p=0;
for(int i=1;i<=n;i++){
if(a[i]-a[p]<mid)num++;
else p=i;
}
return num<=m;
}
void solve(){
cin>>len>>n>>m;
for(int i=1;i<=n;i++)cin>>a[i];
a[n+1]=len;a[0]=0;n++;
int l=1;int r=len;
while(l<r){
int mid=(l+r+1)>>1;
if(check(mid))l=mid;
else r=mid-1;
}
cout<<l<<endl;
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
C.求区间和
Key:前缀和-一维前缀和
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 2e5+10, MAX = 1e9, INF = -1e9;
int n;
int a[N];
int q;
int l,r;
int s[N];
void solve(){
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i];
s[0]=0;
for(int i=1;i<=n;i++)s[i]=s[i-1]+a[i];
cin>>q;
while(q--){
cin>>l>>r;
cout<<s[r]-s[l-1]<<endl;
}
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
D.领地选择
Key:前缀和-二位前缀和
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 1005, MAX = 1e9, INF = -1e9;
int n,m,c;
int a[N][N];
int s[N][N];
int ans=INF;
int x,y;
void solve(){
cin>>n>>m>>c;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
cin>>a[i][j];
}
}
for(int i=0;i<=n;i++)s[i][0]=s[0][i]=0;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+a[i][j];
}
}
for(int i=1;i+c-1<=n;i++){
for(int j=1;j+c-1<=m;j++){
int x0=i;int x1=i+c-1;
int y0=j;int y1=j+c-1;
int ds=s[x1][y1]-s[x0-1][y1]-s[x1][y0-1]+s[x0-1][y0-1];
if(ds>ans){
ans=ds;
x=i;y=j;
}
}
}
cout<<x<<" "<<y<<endl;
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
E.语文成绩
Key:差分-一维差分
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 5e6+10, MAX = 1e9, INF = -1e9;
int n,m;
int a[N];
int l,r,c;
int b[N];
int ans=MAX;
void solve(){
cin>>n>>m;
for(int i=1;i<=n;i++)cin>>a[i];
b[0]=0;
for(int i=1;i<=n;i++)b[i]=a[i]-a[i-1];
while(m--){
cin>>l>>r>>c;
b[l]+=c;b[r+1]-=c;
}
for(int i=1;i<=n;i++){
b[i]+=b[i-1];
ans=min(ans,b[i]);
}
cout<<ans<<endl;
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
F.地毯
Key:差分-二维差分
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 1005, MAX = 1e9, INF = -1e9;
int n,m;
int b[N][N];
int l1,r1,l2,r2;
void insert(int x1,int y1,int x2,int y2,int e){
b[x1][y1]+=e;
b[x2+1][y1]-=e;
b[x1][y2+1]-=e;
b[x2+1][y2+1]+=e;
}
void solve(){
cin>>n>>m;
memset(b,0,sizeof b);
while(m--){
cin>>l1>>r1>>l2>>r2;
insert(l1,r1,l2,r2,1);
}
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
b[i][j]=b[i-1][j]+b[i][j-1]-b[i-1][j-1]+b[i][j];
cout<<b[i][j]<<" ";
}
cout<<endl;
}
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
G.第31次CSP认证第二题：坐标变换（其二）
Key:前缀和
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<int,char> PIC;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<int> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 2e5+10, MAX = 1e9, INF = -1e9;
int n,q;
int i,j;
map<int,int> mpa;
map<int,int> mpb;
double x,y;
vector<double> na;
vector<double> nb;
void solve(){
cin>>n>>q;
na.pb(1.0);nb.pb(0.0);
for(int i=1;i<=n;i++){
cin>>j>>x;
if(j==1){
na.pb(na[na.size()-1]*x);
}
else{
nb.pb(nb[nb.size()-1]+x);
}
mpa[i]=na.size()-1;
mpb[i]=nb.size()-1;
}
while(q--){
cin>>i>>j>>x>>y;
double d=na[mpa[j]]/na[mpa[i-1]];
x*=d;
y*=d;
double x0=x;
double y0=y;
d=nb[mpb[j]]-nb[mpb[i-1]];
x=x0*cos(d)-y0*sin(d);
y=x0*sin(d)+y0*cos(d);
cout<<fixed<<setprecision(3)<<x<<" "<<y<< endl;
}
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
H.第25次CSP认证第二题：出行计划
Key:差分
AC代码
#include<bits/stdc++.h>
#define endl '\n'
#define int int long long
#define pb push_back
#define bs bitset
#define val(a) (a<'a' ? (a-'A'+'a') : a)
#define fast() ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr)
using namespace std;
typedef pair<char,int> PCI;
typedef pair<int,int> PII;
typedef pair<long long, long long> PLL;
typedef priority_queue<PII> PQ;
typedef priority_queue<int, vector<int>, greater<int>> Q;
const int N = 1e6+10, MAX = 1e9, INF = -1e12, M = 10005;
int n,m,k;
int t,c;
int b[N];
int e;
void solve(){
cin>>n>>m>>k;
memset(b,0,sizeof b);
for(int i=1;i<=n;i++){
cin>>t>>c;
int l=max(1ll,t-c+1);
int r=t;
b[l]++;b[r+1]--;
}
for(int i=1;i<N;i++){
b[i]+=b[i-1];
}
while(m--){
cin>>e;
cout<<b[e+k]<<endl;
}
return ;
}
signed main()
{
fast();
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
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