UVA 11019 - Matrix Matcher(AC自动机 | hash大法)

UVA 11019 - Matrix Matcher

题目链接

题意：给定两个矩阵字符串，要求第二个矩阵在第一个矩阵的出现次数

思路：第二个矩阵按行拆分成自动机，然后用第一个矩阵一行一行去匹配，利用一个rc[N][M]的数组记录下每个左上角对应位置的成功匹配次数，然后找完后，对于每个位置，如果成功匹配次数为x，那么就是成功匹配上了，ans++

代码：

#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;

const int MAXNODE = 10005;
const int SIGMA_SIZE = 127;
const int N = 1005;
const int M = 105;

struct AutoMac {

    int ch[MAXNODE][SIGMA_SIZE];
    int val[MAXNODE][105];
    int vn[MAXNODE];
    int next[MAXNODE];
    int last[MAXNODE];
    int sz;

    int n, m, x, y;
    char nm[N][N], xy[M];
    int rc[N][N];

    void init() {
	sz = 1;
	memset(ch[0], 0, sizeof(ch[0]));
    }

    int idx(char c) {
	return c;
    }

    void insert(char *s, int v) {
	int u = 0;
	int n = strlen(s);
	for (int i = 0; i < n; i++) {
	    int c = idx(s[i]);
	    if (!ch[u][c]) {
		memset(ch[sz], 0, sizeof(ch[sz]));
		memset(val[sz], 0, sizeof(val[sz]));
		vn[sz] = 0;
		ch[u][c] = sz++;
	    }
	    u = ch[u][c];
	}
	val[u][vn[u]++] = v;
    }

    void getnext() {
	next[0] = 0;
	queue<int> Q;
	for (int c = 0; c < SIGMA_SIZE; c++) {
	    int u = ch[0][c];
	    if (u) {next[u] = 0; Q.push(u); last[u] = 0;}
	}
	while (!Q.empty()) {
	    int r = Q.front(); Q.pop();
	    for (int c = 0; c < SIGMA_SIZE; c++) {
		int u = ch[r][c];
		if (!u) {
		    ch[r][c] = ch[next[r]][c];
		    continue;
		}
		Q.push(u);
		int v = next[r];
		while (v && !ch[v][c]) v = next[v];
		next[u] = ch[v][c];
		last[u] = val[next[u]] ? next[u] : last[next[u]];
	    }
	}
    }

    void print(int r, int c, int j) {
	if (j) {
	    for (int i = 0; i < vn[j]; i++) {
		if (r - val[j][i] >= 0)
		    rc[r - val[j][i]][c]++;
	    }
	    print(r, c, last[j]);
	}
    }

    void find(int row) {
	int u = 0;
	int n = strlen(nm[row]);
	for (int i = 0; i < n; i++) {
	    int c = idx(nm[row][i]);
	    u = ch[u][c];
	    if (val[u]) print(row, i - y + 1, u);
	    else if (last[u]) print(row, i - y + 1, last[u]);
	}
    }
    
    void solve() {
	memset(rc, 0, sizeof(rc));
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++)
	    scanf("%s", nm[i]);
	scanf("%d%d", &x, &y);
	for (int i = 1; i <= x; i++) {
	    scanf("%s", xy);
	    insert(xy, i);
	}
	getnext();
	for (int i = 1; i <= n; i++)
	    find(i);
	int ans = 0;
	for (int i = 0; i < n; i++) {
	    for (int j = 0; j < m; j++) {
		if (rc[i][j] == x)
		    ans++;
	    }
	}
	printf("%d\n", ans);
    }
};

AutoMac gao;

int main() {
    int t;
    scanf("%d", &t);
    while (t--) {
	gao.init();
	gao.solve();
    }
    return 0;
}

hash大法：

#include <cstdio>
#include <cstring>

typedef unsigned long long ull;

const ull X1 = 100000007, X2 = 1000000007;

const int N = 1005;
const int M = 105;

int t, n, m, x, y;
char a[N][N], b[M][M];
ull H[N][N];

ull gethash() {
    ull ans = 0;
    for (int i = 0; i < x; i++) {
	ull u = 0;
	for (int j = 0; j < y; j++)
	    u = u * X1 + b[i][j];
	ans = ans * X2 + u;
    }
    return ans;
}

int solve() {
    ull u = gethash(), Hp = 1;
    for (int i = 0; i < y - 1; i++)
	Hp *= X1;
    for (int i = 0; i < n; i++) {
	ull sum = 0;
	for (int j = 0; j < y - 1; j++)
	    sum = sum * X1 + a[i][j];
	for (int j = y - 1; j < m; j++) {
	    sum = sum * X1 + a[i][j];
	    H[i][j - y + 1] = sum;
	    sum -= Hp * a[i][j - y + 1];
	}
    }
    int ans = 0;
    Hp = 1;
    for (int i = 0; i < x - 1; i++)
	Hp *= X2;
    for (int j = 0; j < m - y + 1; j++) {
	ull sum = 0;
	for (int i = 0; i < x - 1; i++)
	    sum = sum * X2 + H[i][j];
	for (int i = x - 1; i < n; i++) {
	    sum = sum * X2 + H[i][j];
	    if (sum == u) ans++;
	    sum -= Hp * H[i - x + 1][j];
	}
    }
    return ans;
}

int main() {
    scanf("%d", &t);
    while (t--) {
	scanf("%d%d", &n, &m);
	for (int i = 0; i < n; i++)
	    scanf("%s", a[i]);
	scanf("%d%d", &x, &y);
	for (int i = 0; i < x; i++)
	    scanf("%s", b[i]);
	printf("%d\n", solve());
    }
    return 0;
}