LightOJ - 1081 Square Queries(二维RMQ)

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题目大意：给你一个矩阵，然后Q个询问，询问的是一个矩阵内的最大值

解题思路：惭愧，这题用了暴力＋一维RMQ

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int N = 510;int n, q, cas = 1;int val[N][N];int dp[N][N][10];void init() {    scanf("%d%d", &n, &q);    for (int i = 1; i <= n; i++)        for (int j = 1; j <= n; j++) {            scanf("%d", &val[i][j]);            dp[i][j][0] = val[i][j];        }    for (int i = 1; i <= n; i++) {        for (int j = 1; (1 << j) <= n; j++)            for (int k = 1; k + (1 << j) - 1 <= n; k++) {                dp[i][k][j] = max(dp[i][k][j - 1], dp[i][k + (1 << (j - 1))][j - 1]) ;            }    }}int Query(int i, int x, int y) {    int k = 0;    while (x + (1 << (k + 1)) - 1 <= y) k++;    return max(dp[i][x][k], dp[i][y - (1 << k) + 1][k]);}void solve() {    int i, j, s;    printf("Case %d:\n", cas++);    while (q--) {        scanf("%d%d%d", &i, &j, &s);        int ans = 0;        for (int k = i; k < i + s; k++) {            ans = max(ans, Query(k, j, j + s - 1));        }        printf("%d\n", ans);    }}int main() {    int test;    scanf("%d", &test);    while (test--) {        init();        solve();    }    return 0;}

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