pku 2580 约束扩散

 

#include <iostream> #include <cstring> #include <vector> using namespace std; long n, m; char str[30]; vector < vector < vector <long> > > V; long arr[110]; bool vist[110], isCan[110][110]; void solution() { if (m == 0) { puts("YES"); return; } long i, j, k, havekey = 0; memset(vist, 0, sizeof(vist)); vist[m] = true; havekey |= arr[m]; bool flag = true; while (flag) { flag = false; for (i = 0; i < n; ++i) { if (vist[i]) { for (j = 0; j < n; ++j) { if (isCan[i][j] && !vist[j]) { for (k = 0; k < V[i][j].size(); ++k) { if ((havekey & V[i][j][k]) == V[i][j][k] && !vist[j]) { havekey |= arr[j]; vist[j] = true; flag = true; if (j == 0) { puts("YES"); return; } } } } } } } } puts("NO"); } int main() { long i; char ch; while (scanf("%s", str) != EOF) { if (!strcmp(str, "ENDOFINPUT")) { break; } memset(isCan, 0, sizeof(isCan)); memset(arr, 0, sizeof(arr)); scanf("%ld %ld", &m, &n); V.clear(); V.resize(n); for (i = 0; i < n; ++i) { V[i].resize(n); } getchar(); for (i = 0; i < n; ++i) { long num = 0, state = 0; bool flag = false; while (scanf("%c", &ch)) { if (ch == ' ' || ch == '\n') { if (flag) { V[i][num].push_back(state); V[num][i].push_back(state); isCan[i][num] = isCan[num][i] = true; num = state = 0; flag = false; } } else if (ch >= '0' && ch <= '9') { flag = true; num = num*10+ch-'0'; } else if (ch >= 'A' && ch <= 'Z') { state |= (1<<(ch-'A')); } if (ch == '\n') { break; } } } for (i = 0; i < n; ++i) { while (scanf("%c", &ch)) { if (ch >= 'A' && ch <= 'Z') { arr[i] |= (1<<(ch-'A')); } if (ch == '\n') { break; } } } gets(str); solution(); } return 0; }