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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#649101 | #5407. 基础图论练习题 | ddxrS | 0 | 6ms | 4376kb | C++14 | 1.7kb | 2024-10-17 21:37:08 | 2024-10-17 21:37:09 |
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 - '0') : (10 + (x - 'A')));}
void solve() {
scanf("%lld", &n);
for(int i = 1; i <= n; i++) out[i] = 0;
for(int i = 1; i <= n; i++) for(int j = 1; j <= n; j++) flg[i][j] = false;
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;
for(int i = 1; i <= n; i++) nxt[sum[i]]++;
sort(sum + 1, sum + n + 1);
for(int i = 1; i <= n; 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] - 1 == p) 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], x = i, y = j;
if(flg[x][y]) swap(x, y);
if(out[x] >= out[y]) sum += (cnt2[nxt[out[x]] - 1] - cnt2[nxt[out[y] - 1]]);
if(out[x] + 1 < out[y]) sum -= (cnt1[nxt[out[y] - 1]] - cnt1[nxt[out[x]] - 1]);
ans = (ans * 2 + sum) % mod;
}
printf("%lld\n", ans);
}
signed main() {
int t; cin>>t;
while(t--) solve();
return 0;
}
詳細信息
Subtask #1:
score: 0
Wrong Answer
Test #1:
score: 0
Wrong Answer
time: 6ms
memory: 4376kb
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 249478223 372704292 205 0 7359 2 140046316 274726919 451356899 196152 2 171266846 220 14892539 4541 0 764279207 239880604 16983811 243844 146149 14859530 394935724 317960730 225522696 369384022 522465179 340022 298552802 891887445 196602 31195129 240650340 718425409 252 252 241 14680057...
result:
wrong answer 3rd numbers differ - expected: '285212672', found: '249478223'
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%