RMQ模板

模板对应POJ 3264

#include <cstring>#include <cmath>#include <cstdio>#include <algorithm>#define N 50010using namespace std;int maxArr[N][16], minArr[N][16];int n, q, num[N];void Sparse_Table(){int l = (int)(log((double)n) / log(2.0));for (int j = 1;j <= l;j++)for (int i = 1; i + (1 << (j - 1) ) - 1 <= n;++i){maxArr[i][j] = max(maxArr[i][j - 1], maxArr[i + (1 << (j - 1))][j - 1]);minArr[i][j] = min(minArr[i][j - 1], minArr[i + (1 << (j - 1))][j - 1]);}}int rmq(int l, int r){int k = (int)(log((double)(r - l + 1)) / log(2.0));int Max = max(maxArr[l][k], maxArr[r - (1 << k) + 1][k]);int Min = min(minArr[l][k], minArr[r - (1 << k) + 1][k]);return Max - Min;}int main(){while (~scanf("%d %d", &n, &q)){memset(maxArr, 0, sizeof(maxArr));memset(minArr, 0, sizeof(minArr));for (int i = 1;i <= n;i++){scanf("%d", &num[i]);maxArr[i][0] = minArr[i][0] = num[i];}Sparse_Table();int l, r;while (q--){scanf("%d%d", &l, &r);printf("%d\n", rmq(l, r));}}return 0;}