# 第三届“传智杯”全国大学生IT技能大赛（初赛A组）题解

## C - 志愿者

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
char c = getchar(); int x = 0, f = 1;
while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x * f;
}
struct Node {
int t, k, id;
bool operator < (const Node &b) const {
if(t * k > b.t * b.k) return 1;
else if(t * k < b.t * b.k) return 0;

if(t > b.t) return 1;
else if(t < b.t) return 0;

return id < b.id;
}
}a[MAXN];
int main() {
for(int i = 1; i <= N; i++) {
a[i].id = i;
}
sort(a + 1, a + N + 1);
for(int i = 1; i <= N; i++)
cout << a[i].id << ' ';
return 0;
}

## D - 终端

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
char c = getchar(); int x = 0, f = 1;
while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x * f;
}
map<string, int> mp;
string opt;
int main() {
#ifndef ONLINE_JUDGE
freopen("a.in", "r", stdin);
#endif
for(int i = 1; i <= N; i++) {
cin >> opt;
if(opt == "touch") {
string fn;
cin >> fn;
if(mp.find(fn) != mp.end()) continue;
mp[fn] = i;
} else if(opt == "rm") {
string fn;
cin >> fn;
if(mp.find(fn) == mp.end()) continue;
mp.erase(fn);
} else if(opt == "ls") {
vector<pair<int, string>> tmp;
for(auto &x: mp) {
tmp.push_back(make_pair(x.second, x.first));
}
sort(tmp.begin(), tmp.end());
for(auto x: tmp)
cout << x.second << '\n';
} else if(opt == "rename") {
string s1, s2;
cin >> s1 >> s2;
if(mp.find(s1) == mp.end()) continue;
int tmp = mp[s1];
mp.erase(s1);
mp[s2] = tmp;
}
}
return 0;
}

## E - 运气

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
const int mod = 1e9 + 7;
#define LL long long
char c = getchar(); int x = 0, f = 1;
while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x * f;
}
LL N, K, ans;
void dfs(int x, LL val) {
if(x == N + 1) {
ans += (val % K == 0);
return ;
}
for(int i = 1; i <= 6; i++)
dfs(x + 1, val * 10 + i);
}
int main() {
#ifndef ONLINE_JUDGE
freopen("a.in", "r", stdin);
#endif
dfs(1, 0);
cout << ans % mod;
return 0;
}

## F - 游戏

emmm，，至于为什么，，可以从联通块中抽出一个树来，显然每次从叶子节点删，一定满足条件。

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
const int mod = 1e9 + 7;
#define LL long long
char c = getchar(); int x = 0, f = 1;
while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x * f;
}
int N, c1, c2, a[MAXN], vis[MAXN];
LL cnt = 0, ans;
vector<int> v[MAXN];
void dfs(int x) {
cnt++;
vis[x] = 1;
for(auto &to: v[x]) {
if(!vis[to])
dfs(to);
}
}
void dfs2(int i) {
cnt++;
vis[i] = 1;
for(int j = 1; j <= N; j++) {
if(__builtin_popcount(a[i] ^ a[j]) != 1 && i != j && vis[j] == 0) {
dfs2(j);
}
}
}
int main() {
#ifndef ONLINE_JUDGE
freopen("a.in", "r", stdin);
#endif
for(int i = 1; i <= N; i++) a[i] = read();
if(c1 == c2) cout << 1ll * (N - 1) * c1;
else if(c1 < c2) {
for(int i = 1; i <= N; i++)
for(int j = 1; j <= N; j++)
if(__builtin_popcount(a[i] ^ a[j]) == 1 && i != j)
v[i].push_back(j);
LL sum = N;
for(int i = 1; i <= N; i++) {
if(!vis[i]) {
dfs(i);
ans += 1ll * (cnt - 1) * c1;
sum -= (cnt - 1);
cnt = 0;
}
}
ans += 1ll * (sum - 1) * c2;
cout << ans << '\n';
} else {
LL sum = N;
for(int i = 1; i <= N; i++) {
if(!vis[i]) {
dfs2(i);
ans += 1ll * (cnt - 1) * c2;
sum -= (cnt - 1);
cnt = 0;
}
}
ans += 1ll * (sum - 1) * c1;
cout << ans << '\n';
}
return 0;
}
/*

*/

## G - 森林

(好久没打比赛，开场还以为是个LCT，后来又想操作子树的好像是ETT，不过还好及时终止了自己的危险想法)

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
const int mod = 1e9 + 7;
#define LL long long
char c = getchar(); int x = 0, f = 1;
while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x * f;
}
int N, M;
int fa[MAXN], sum[MAXN];
struct Edge {
int u, v;
}E[MAXN];
struct Opt {
int opt, a, b;
}op[MAXN];
int val[MAXN], flag[MAXN];
int find(int x) {
return x == fa[x] ? x : fa[x] = find(fa[x]);
}
void unionn(int x, int y) {
int fx = find(x), fy = find(y);
sum[fy] += sum[fx];
sum[fx] = 0;
fa[fx] = fy;
}
int query(int x) {
return sum[find(x)];
}
vector<int> ans;
int main() {
#ifndef ONLINE_JUDGE
freopen("a.in", "r", stdin);
#endif
for(int i = 1; i <= N; i++) val[i] = read(), fa[i] = i;
for(int i = 1; i < N; i++) {
}
for(int i = 1; i <= M; i++) {
if(op[i].opt == 1) {
flag[op[i].a] = 1;
} else if(op[i].opt == 2) {
int tmp = val[op[i].a];//Ö®Ç°µÄval
val[op[i].a] = op[i].b;
op[i].b = tmp;
} else {
}
}
for(int i = 1; i <= N; i++) sum[i] = val[i];
for(int i = 1; i < N; i++) {
if(!flag[i]) {//not delet
unionn(E[i].u, E[i].v);
}

}
for(int i = M; i >= 1; i--) {
if(op[i].opt == 1) {
int id = op[i].a;
unionn(E[id].u, E[id].v);
} else if(op[i].opt == 2) {
int id = op[i].a, pre = val[id];
int fx = find(id);
sum[fx] -= pre;
sum[fx] += op[i].b;
val[id] = op[i].b;
} else {
ans.push_back(query(op[i].a));
}
}

reverse(ans.begin(), ans.end());
for(auto &x: ans) cout << x << '\n';
return 0;
}
/*

*/
posted @ 2020-12-20 20:33  自为风月马前卒  阅读(3637)  评论(6编辑  收藏  举报