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ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#649031 | #5407. 基础图论练习题 | lifan | 0 | 15ms | 4364kb | C++14 | 1.8kb | 2024-10-17 21:20:57 | 2024-10-17 21:21:00 |
Judging History
answer
//
/*
由兰道定理得,竞赛图的强连通分量个数为 $\sum_{i=1}^{n}[\sum_{j=1}^i out_j=C(i,2)]$。
每次反转一条边可以做到 O(1) 修改。
*/
#include<bits/stdc++.h>
#define int long long
typedef long long ll;
using namespace std;
const int N = 5005;
const ll mod = 1e9 + 7;
bool flg[N][N];
int n;
char s[N];
int out[N], sum[N], nxt[N];
int cnt1[N], cnt2[N];
int turn(char x) {return (x >= '0' && x <= '9' ? (x ^ 48) : (10 + (x - 'A')));}
void solve() {
scanf("%lld", &n);
for(int i = 1; i <= n; i++) out[i] = 0;
for(int i = 2, l; i <= n; i++) { l = (i - 1) / 4 + 1;
cin>>(s + 1);
for(int j = 1; j <= l; j++) for(int k = 4 * j - 3, x = turn(s[j]); k <= 4 * j && k < i; k++, x >>= 1)
if(x & 1) flg[i][k] = true, flg[k][i] = false, out[i]++;
else flg[k][i] = true, flg[i][k] = false, out[k]++;
}
for(int i = 1; i <= n; i++) sum[i] = out[i], nxt[i] = 0;
sort(sum + 1, sum + n + 1);
for(int i = 1; i <= n; i++) nxt[sum[i]] = i;
for(int i = 1; i <= n; i++) if(!nxt[i]) nxt[i] = nxt[i - 1];
for(int i = 1; i <= n; i++) {
int p = i * (i - 1) / 2; sum[i] += sum[i - 1];
if(sum[i] == p) cnt1[i] = cnt1[i - 1] + 1;
else if(sum[i] == p + 1) cnt2[i] = cnt2[i - 1] + 1;
}
ll ans = 0;
for(int i = n; i >= 1; i--) for(int j = i - 1; j >= 1; j--) {
int sum = cnt1[n];
if(flg[i][j]) {
if(out[j] >= out[i]) sum += (cnt2[nxt[out[j]] - 1] - cnt2[nxt[out[i] - 1]]);
if(out[j] + 1 < out[i]) sum -= (cnt1[nxt[out[i] - 1]] - cnt1[nxt[out[j]] - 1]);
} else {
if(out[i] >= out[j]) sum += (cnt2[nxt[out[i]] - 1] - cnt2[nxt[out[j] - 1]]);
if(out[i] + 1 < out[j]) sum -= (cnt1[nxt[out[j] - 1]] - cnt1[nxt[out[i]] - 1]);
}
ans = (ans * 2 + sum) % mod;
}
printf("%lld\n", ans);
}
signed main() {
int t; cin>>t;
while(t--) solve();
return 0;
}
Details
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Subtask #1:
score: 0
Wrong Answer
Test #1:
score: 0
Wrong Answer
time: 15ms
memory: 4364kb
input:
10000 100 1 2 2 8 C0 F0 27 78 AE1 C01 511 D87 EF20 3873 2742 73D0 DC9B0 FB2A3 9C011 9B4E0 95DC00 A7B980 F43531 6A6245 5347BE0 1A6C8A1 88E46D6 64CF3AE D25F63C1 C894E4C3 1C0AFD73 EC1C3F9A 087CE17C0 22149A380 B28038AF1 B9CA21C7F D78F5307C1 49045489A2 72C4DE6FD1 7713F40D05 EEE8878EEC1 310E62812B1 DA9D5B...
output:
281603732 13 251113734 327455501 270 0 1983 2 446245363 989995365 888991962 195933 2 891483044 292 13878907 4569 0 202648588 119205755 10947080 152228 273828 15660107 401646784 79291948 422209336 388020715 936825725 122525 489271649 202620276 146878 6121431 7582599 897859329 269 256 345 20962439 987...
result:
wrong answer 3rd numbers differ - expected: '285212672', found: '251113734'
Subtask #2:
score: 0
Skipped
Dependency #1:
0%
Subtask #3:
score: 0
Skipped
Dependency #1:
0%
Subtask #4:
score: 0
Skipped
Dependency #1:
0%
Subtask #5:
score: 0
Skipped
Dependency #1:
0%