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ZOJ 3497 Mistwald 矩阵

利用可达矩阵的幂来判断是否可达

#include <cstdio>#include <cstring>#include <algorithm>#include <queue>#include <stack>#include <map>#include <set>#include <climits>#include <iostream>#include <string>using namespace std; #define MP make_pair#define PB push_backtypedef long long LL;typedef unsigned long long ULL;typedef vector<int> VI;typedef pair<int, int> PII;typedef pair<double, double> PDD;const int INF = INT_MAX / 3;const double eps = 1e-8;const LL LINF = 1e17;const LL MOD = LINF;const double DINF = 1e60;const int maxn = 30;struct Matrix {    int n, m;    LL data[maxn][maxn];    Matrix(int n = 0, int m = 0): n(n), m(m) {        memset(data, 0, sizeof(data));    }    void print() {        for(int i = 1; i <= n; i++) {            for(int j = 1; j <= m; j++) {                cout << data[i][j] << " ";            }            cout << endl;        }    }}; Matrix operator * (Matrix a, Matrix b) {    Matrix ret(a.n, b.m);    for(int i = 1; i <= a.n; i++) {        for(int j = 1; j <= b.m; j++) {            for(int k = 1; k <= a.m; k++) {                ret.data[i][j] += a.data[i][k] * b.data[k][j];                ret.data[i][j] %= MOD;            }        }    }    return ret;} Matrix operator + (Matrix a, Matrix b) {    for(int i = 1; i <= a.n; i++) {        for(int j = 1; j <= a.m; j++) {            a.data[i][j] += b.data[i][j];            a.data[i][j] %= MOD;        }    }    return a;}Matrix operator * (int p, Matrix mat) {    for(int i = 1; i <= mat.n; i++) {        for(int j = 1; j <= mat.m; i++) {            mat.data[i][j] *= p;            mat.data[i][j] %= MOD;        }    }} Matrix pow(Matrix mat, LL p) {    if(p == 0) {        Matrix ret(mat.n, mat.m);        for(int i = 1; i <= mat.n; i++) ret.data[i][i] = 1;        return ret;    }    if(p == 1) return mat;    Matrix ret = pow(mat * mat, p / 2);    if(p & 1) ret = ret * mat;    return ret;}int n, m;int main() {    int T; scanf("%d", &T);    while(T--) {        scanf("%d%d", &n, &m);        Matrix mat(n * m, n * m);        for(int i = 1; i <= n; i++) {            for(int j = 1; j <= m; j++) {                int nowx = i - 1, nowy = j - 1, nx, ny;                char tmp; scanf(" %c", &tmp);                for(int k = 0; k < 4; k++) {                    if(k) scanf(" %c", &tmp);                    scanf("(%d,%d)", &nx, &ny);                    nx--; ny--;                    if(i == n && j == m) continue;                    mat.data[nowx * m + nowy + 1][nx * m + ny + 1] = 1;                }                scanf(" %c", &tmp);            }        }        int Q; scanf("%d", &Q);        while(Q--) {            int K; scanf("%d", &K);            Matrix ret = pow(mat, K);            if(ret.data[1][n * m] == 0) puts("False");            else {                int cnt = 0;                for(int i = 1; i < n * m; i++) {                    if(ret.data[1][i] != 0) cnt++;                }                if(cnt == 0) puts("True");                else puts("Maybe");            }        }        puts("");    }    return 0;}

  

ZOJ 3497 Mistwald 矩阵