RMQ模板


int d_min[maxn][maxm], d_max[maxn][maxm];//值
int minpos[maxn][maxm], maxpos[maxn][maxm];//下标

//预处理区间最大最小值
void RMQ_init(int n){
    int i, j;
    for (i = 1; i <= n; i++){
        d_min[i][0] = a[i];
        d_max[i][0] = a[i];
    }
    for (j = 1; (1 << j) <= n; j++)
        for (i = 1; i + j - 1 <= n; i++){
            d_min[i][j] = min(d_min[i][j - 1], d_min[i + (1 << (j - 1))][j - 1]);
            d_max[i][j] = max(d_max[i][j - 1], d_max[i + (1 << (j - 1))][j - 1]);
        }
}

//查询区间最小值
int RMQ_min(int l, int r){
    int k = 0;
    while ((1 << (k + 1)) <= r - l + 1) k++;
    return min(d_min[l][k], d_min[r - (1 << k) + 1][k]);
}

//查询区间最大值
int RMQ_max(int l, int r){
    int k = 0;
    while ((1 << (k + 1)) <= r - l + 1) k++;
    return max(d_max[l][k], d_max[r - (1 << k) + 1][k]);
}

//预处理区间最大最小值的下标
void RMQ_pos_init(int n, int b[]){
    int i, j;
    for (i = 1; i <= n; i++) {
        maxpos[i][0] = i;
        minpos[i][0] = i;
    }
    for (j = 1; (1 << j) <= n; j++)
        for (i = 1; i + (1 << j) - 1 <= n; i++){
            minpos[i][j] = b[minpos[i][j - 1]] < b[minpos[i + (1 << (j - 1))][j - 1]] ? minpos[i][j - 1] : minpos[i + (1 << (j - 1))][j - 1];
            maxpos[i][j] = b[maxpos[i][j - 1]] > b[maxpos[i + (1 << (j - 1))][j - 1]] ? maxpos[i][j - 1] : maxpos[i + (1 << (j - 1))][j - 1];
        }

}
//查询区间最大值的下标
int RMQ_pos_max(int s, int v, int b[]){
    int k = (int)(log((v - s + 1)*1.0) / log(2.0));
    return b[maxpos[s][k]] > b[maxpos[v - (1 << k) + 1][k]] ? maxpos[s][k] : maxpos[v - (1 << k) + 1][k];
}

//查询区间最小值的下标
int RMQ_pos_min(int s, int v, int b[]){
    int k = (int)(log((v - s + 1)*1.0) / log(2.0));
    return b[minpos[s][k]] < b[minpos[v - (1 << k) + 1][k]] ? minpos[s][k] : minpos[v - (1 << k) + 1][k];
}

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原文地址:https://www.cnblogs.com/romaLzhih/p/9489799.html