线段树水题 #1077 : RMQ问题再临-线段树

#include 
#include 
#include 
#include 
#include 

using namespace std;
#define maxn 1000000 + 10
#define Lson L, mid, root<<1
#define Rson mid+1, R, root<<1|1
#define INF 0x7ffffff

int Min[maxn<<2], a[maxn];
int num;

void Pushup(int root)
{
    Min[root] = min(Min[root<<1], Min[root<<1|1]);
}

void Bulid(int L, int R, int root)
{
    if(L == R)
    {
        Min[root] = a[++num];
        return ;
    }
    int mid = (L + R) >> 1;
    Bulid(Lson);
    Bulid(Rson);
    Pushup(root);
}

void Update(int q, int val, int L, int R, int root)
{
    if(L == R)
    {
        Min[root] = val;
        return ;
    }
    int mid = (L + R) >> 1;
    if(q <= mid) Update(q, val, Lson);
    else Update(q, val, Rson);
    Pushup(root);
}

int Query(int l, int r, int L, int R, int root)
{
    if(l<=L && r>=R)
    {
        return Min[root];
    }
    int res = INF;
    int mid = (L + R) >> 1;
    if(l <= mid) res = min(res, Query(l, r, Lson));
    if(r > mid) res = min(res, Query(l, r, Rson));
    return res;
}

int main()
{
    int n, q;
    while(~scanf("%d", &n))
    {
        for(int i=1; i<=n; i++)
            scanf("%d", &a[i]);
        num = 0;
        Bulid(1, n, 1);

        scanf("%d", &q);
        int k1, k2, k3;
        while(q--)
        {
            scanf("%d%d%d", &k1, &k2, &k3);
            if(k1) Update(k2, k3, 1, n, 1);
            else printf("%d\n", Query(k2, k3, 1, n, 1));
        }
    }
    return 0;
}