题目链接
简单的二维线段树求区间最小值问题，还不用修改操作。
#include <iostream>
#include <cstdio>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <limits>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#define lowbit(x) ( x&(-x) )
#define pi 3.141592653589793
#define e 2.718281828459045
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const int maxN = 305;
int N, Q, a[maxN][maxN], tree[maxN<<2][maxN<<2];
void build_In(int rt, int fa, int l, int r, bool flag, int pos)
{
if(l == r)
{
if(flag) tree[fa][rt] = a[pos][l];
else tree[fa][rt] = min(tree[fa<<1][rt], tree[fa<<1|1][rt]);
return;
}
int mid = (l + r)>>1;
build_In(rt<<1, fa, l, mid, flag, pos);
build_In(rt<<1|1, fa, mid+1, r, flag, pos);
tree[fa][rt] = min(tree[fa][rt<<1], tree[fa][rt<<1|1]);
}
void build_Out(int rt, int l, int r)
{
if(l == r)
{
build_In(1, rt, 1, N, true, l);
return;
}
int mid = (l + r)>>1;
build_Out(rt<<1, l, mid);
build_Out(rt<<1|1, mid+1, r);
build_In(1, rt, 1, N, false, 0);
}
int query_In(int rt, int fa, int l, int r, int ql, int qr)
{
if(ql<=l && qr>=r) return tree[fa][rt];
int mid = (l + r)>>1;
if(ql>mid) return query_In(rt<<1|1, fa, mid+1, r, ql, qr);
else if(qr<=mid) return query_In(rt<<1, fa, l, mid, ql, qr);
else
{
int ans = query_In(rt<<1|1, fa, mid+1, r, ql, qr);
ans = min(ans, query_In(rt<<1, fa, l, mid, ql, qr));
return ans;
}
}
int query_Out(int rt, int l, int r, int qlx, int qly, int qrx, int qry)
{
if(qlx<=l && qrx>=r) return query_In(1, rt, 1, N, qly, qry);
int mid = (l + r)>>1;
if(qlx>mid) return query_Out(rt<<1|1, mid+1, r, qlx, qly, qrx, qry);
else if(qrx<=mid) return query_Out(rt<<1, l, mid, qlx, qly, qrx, qry);
else
{
int ans = query_Out(rt<<1|1, mid+1, r, qlx, qly, qrx, qry);
ans = min(ans, query_Out(rt<<1, l, mid, qlx, qly, qrx, qry));
return ans;
}
}
int main()
{
int T; scanf("%d", &T);
while(T--)
{
scanf("%d", &N);
for(int i=1; i<=N; i++) for(int j=1; j<=N; j++) scanf("%d", &a[i][j]);
build_Out(1, 1, N);
scanf("%d", &Q);
while(Q--)
{
int lx, ly, rx, ry;
scanf("%d%d%d%d", &lx, &ly, &rx, &ry);
printf("%d\n", query_Out(1, 1, N, lx, ly, rx, ry));
}
}
return 0;
}