hihoCoder 1070 RMQ問題再臨

#include <bits/stdc++.h>
#define N 10005
using namespace std;

struct node{
    int l,r,mid,minn;
}tree[N<<2];
int a[N];

void build(int m,int l,int r){
    tree[m].l = l;
    tree[m].r = r;
    tree[m].mid = (l+r)>>1;
    if(l == r){
        tree[m].minn = a[l];
        return;
    }
    build(m<<1,l,tree[m].mid);
    build((m<<1)+1,tree[m].mid+1,r);
    tree[m].minn = min(tree[m<<1].minn,tree[(m<<1)+1].minn);
}

void update(int m,int a,int val){
    if(tree[m].l == a && tree[m].r == a){
        tree[m].minn = val;
        return;
    }
    if(a <= tree[m].mid)
        update(m<<1,a,val);
    else
        update((m<<1)+1,a,val);
    tree[m].minn = min(tree[m<<1].minn,tree[(m<<1)+1].minn);
}

int query(int m,int l,int r){
    if(l == tree[m].l && r == tree[m].r)
        return tree[m].minn;
    if(r <= tree[m].mid)
        return query(m<<1,l,r);
    if(l > tree[m].mid)
        return query((m<<1)+1,l,r);
    return min(query(m<<1,l,tree[m].mid),query((m<<1)+1,tree[m].mid+1,r));
}

int main(){
    int n,m;
    while(scanf("%d",&n) != EOF){
        for(int i = 1; i <= n; i++)
            scanf("%d",&a[i]);
        build(1,1,n);
        scanf("%d",&m);
        int op,x,y;
        for(int i = 0; i < m; i++){
            scanf("%d%d%d",&op,&x,&y);
            if(op == 0)
                printf("%d\n",query(1,x,y));
            else
                update(1,x,y);
        }
    }
    return 0;
}