BZOJ2208

LINK:http://www.lydsy.com/JudgeOnline/problem.php?id=2208

MD水题

正解应该是Trajan缩点+递推

但是暴力O（nm）都能跑10s内

这题就太思博了吧

#include <bits/stdc++.h>
using namespace std;
#define Maxlen (50005 << 2) * 300
char buf[Maxlen], *c = buf;
int Len;

void init() {
    Len = fread(c, 1, Maxlen, stdin);
    buf[Len] = '';
}

template <typename T>
inline T read() {
    register T x = 0, f = 1;
    while (!isdigit(*c)) {
        if (*c == '-')f = -1; ++c;
    }
    while (isdigit(*c)) {
        x = x * 10 + *c - '0'; ++c;
    }
    return x * f;
}

template <typename T>
inline T sread() {
    register T x = 0, f = 1;
    while (!isdigit(*c)) {
        if (*c == '-')f = -1; ++c;
    }
    x = *c - '0'; ++c;
    return x * f;
}

#define read() read<int>()
#define sread() sread<int>()
/*------------------------------template------------------------------*/

int visited[2020];
int n, cnt = 0;
vector<int> edge[2020];
int dfs(int k) {
    int ret = 0;
    for (int i = 0; i < edge[k].size(); i ++) 
        if (!visited[edge[k][i]]){
            visited[edge[k][i]] = 1;
            ret += dfs(edge[k][i]) + 1;
    }
    return ret;
}

int main() {
    init();
    n = read();
    for (int i = 1; i <= n; i ++) {
        for (int j = 1; j <= n;j ++) {
            int x = sread();
            if (x) {
                edge[i].push_back(j);
            }
        }
    } int ans = 0;
    for (int i = 1; i <= n; i ++) {
        memset(visited, 0, sizeof(visited));
        visited[i] = 1;
        ans += dfs(i) + 1;
    }
    printf("%d
", ans);
}