hicoder

RMQ:

#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = a;i <= b;++ i)
#define per(i,a,b) for(int i = a;i >= b;-- i)
#define mem(a,b) memset((a),(b),sizeof((a)))
#define FIN freopen("in.txt","r",stdin)
#define IO ios_base::sync_with_stdio(0),cin.tie(0)
#define pb push_back
using namespace std;
typedef long long LL;
typedef pair<int, int> PIR;
const int N = 1e6+5;

int n, m, l, r, mm[N], a[N], dp[N][20];

void RMQ_init(){
    rep(i, 1, n)    dp[i][0] = a[i];
    for(int j = 1; (1<<j) <= n; ++j){
        for(int i = 0; i+(1<<j)-1 <= n; ++i)
            dp[i][j] = min(dp[i][j-1], dp[i+(1<<(j-1))][j-1]);
    }
}
int RMQ(int l, int r){
    int k = 0;
    while(1<<(k+1) <= r-l+1)    k++;
    return min(dp[l][k], dp[r-(1<<k)+1][k]);
}
int main()
{//IO;
    //FIN;
    scanf("%d", &n);
    rep(i, 1, n)    scanf("%d", &a[i]);
    RMQ_init();
    scanf("%d", &m);
    while(m--){
        scanf("%d%d", &l, &r);
        printf("%d
", RMQ(l, r));
    }
    return 0;
}

 线段树：

#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = a;i <= b;++ i)
#define per(i,a,b) for(int i = a;i >= b;-- i)
#define mem(a,b) memset((a),(b),sizeof((a)))
#define FIN freopen("in.txt","r",stdin)
#define IO ios_base::sync_with_stdio(0),cin.tie(0)
#define pb push_back
#define mid ((l+r)>>1)
#define ls (id<<1)
#define rs ((id<<1)|1)
using namespace std;
typedef long long LL;
typedef pair<int, int> PIR;
const int N = 1e6+5;

int n, m, op, x, y, a[N];

struct Node{
    int minn;
}node[N*4];
void pushUp(int id, int l, int r){
    node[id].minn = min(node[ls].minn, node[rs].minn);
}
void build(int id, int l, int r){
    if(l == r)  { node[id].minn = a[l]; return; }
    build(ls, l, mid);
    build(rs, mid+1, r);
    pushUp(id, l, r);
}
void update(int id, int l, int r, int p, int val){
    if(l == r && l == p)    { node[id].minn = val; return; }
    if(p <= mid)    update(ls, l, mid, p, val);
    else    update(rs, mid+1, r, p, val);
    pushUp(id, l, r);
}
int query(int id, int l, int r, int ql, int qr){
    if(l == ql && r == qr)  return node[id].minn;
    if(qr <= mid)   query(ls, l, mid, ql, qr);
    else if(ql > mid)   query(rs, mid+1, r, ql, qr);
    else{
        return min(query(ls, l, mid, ql, mid), query(rs, mid+1, r, mid+1, qr));
    }
}
int main()
{IO;
    //FIN;
    scanf("%d", &n);
    rep(i, 1, n)    scanf("%d", &a[i]);
    build(1, 1, n);
    scanf("%d", &m);
    while(m--){
        scanf("%d %d", &x, &y);
        printf("%d
", query(1, 1, n, x, y));
    }
    return 0;
}