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
1 #include <bits/stdc++.h> 2 using namespace std; 3 #define Maxlen (50005 << 2) * 300 4 char buf[Maxlen], *c = buf; 5 int Len; 6 7 void init() { 8 Len = fread(c, 1, Maxlen, stdin); 9 buf[Len] = '\0'; 10 } 11 12 template <typename T> 13 inline T read() { 14 register T x = 0, f = 1; 15 while (!isdigit(*c)) { 16 if (*c == '-')f = -1; ++c; 17 } 18 while (isdigit(*c)) { 19 x = x * 10 + *c - '0'; ++c; 20 } 21 return x * f; 22 } 23 24 template <typename T> 25 inline T sread() { 26 register T x = 0, f = 1; 27 while (!isdigit(*c)) { 28 if (*c == '-')f = -1; ++c; 29 } 30 x = *c - '0'; ++c; 31 return x * f; 32 } 33 34 #define read() read<int>() 35 #define sread() sread<int>() 36 /*------------------------------template------------------------------*/ 37 38 int visited[2020]; 39 int n, cnt = 0; 40 vector<int> edge[2020]; 41 int dfs(int k) { 42 int ret = 0; 43 for (int i = 0; i < edge[k].size(); i ++) 44 if (!visited[edge[k][i]]){ 45 visited[edge[k][i]] = 1; 46 ret += dfs(edge[k][i]) + 1; 47 } 48 return ret; 49 } 50 51 int main() { 52 init(); 53 n = read(); 54 for (int i = 1; i <= n; i ++) { 55 for (int j = 1; j <= n;j ++) { 56 int x = sread(); 57 if (x) { 58 edge[i].push_back(j); 59 } 60 } 61 } int ans = 0; 62 for (int i = 1; i <= n; i ++) { 63 memset(visited, 0, sizeof(visited)); 64 visited[i] = 1; 65 ans += dfs(i) + 1; 66 } 67 printf("%d\n", ans); 68 }
