RMQ（线段树实现）

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T_T第一个线段树程序，还没A过题，不过也很感动，先贴出来

//下标从0开始，输入-1 -1 结束.求每一段区间之间的最大值。

#include <cstdio>#include <cstdlib>typedef struct Treenode{    int ld, rd;    struct Treenode *lc, *rc;    int key;}node;int mymax(int a, int b){    return a > b ? a : b;}node* buildtree(int a, int b){    node *p = (node *)malloc(sizeof(node));    p -> ld = a;    p -> rd = b;    p -> key = -1;    if (a == b){        return p;    }    p -> lc = buildtree(a, (a + b) / 2);    p -> rc = buildtree((a + b) / 2 + 1, b);    return p;}void insert(node *T, int pos, int key){    if (T -> ld == T -> rd){        T -> key = key;        return ;    }    if (pos <= (T -> ld + T -> rd) / 2){        insert(T -> lc, pos, key);    }    else{        insert(T -> rc, pos, key);    }    T -> key = mymax(T -> lc -> key, T -> rc -> key);}int search(node *T, int a, int b){    int res = -999999999;    if (a <= T -> ld && T -> rd <= b){        return T -> key;    }    if (a <= (T -> ld + T -> rd) / 2){        res = mymax(search(T -> lc, a, b), res);    }    if (b > (T -> ld + T -> rd) / 2){        res = mymax(search(T -> rc, a, b), res);    }    return res;}int main(void){    int arr[11] = {1, 3, 646, 34, 20, 30 , 60 , 36, 892, 1, -1};    int left, right;    int i, j;    node *linetree = buildtree(0, 10);    for (i = 0; i < 11; i++){        insert(linetree, i, arr[i]);    }    while (scanf("%d%d", &left, &right), left != -1 || right != -1){        printf("%d -- %d:  %d\n", left, right, search(linetree, left, right));    }    return 0;}