线段树水题 #1077 : RMQ问题再临-线段树

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#include <iostream>#include <cstdio>#include <cstring>#include <string>#include <algorithm>using namespace std;#define maxn 1000000 + 10#define Lson L, mid, root<<1#define Rson mid+1, R, root<<1|1#define INF 0x7ffffffint 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;}

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