HDU_1166 敌兵布阵 【线段树】

题目描述

解题思路

代码部分

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#define lc left, mid, root << 1
#define rc mid + 1, right, root << 1 | 1
using namespace std;

const int maxn = 5e4 + 10;
int sum[maxn << 2];

void push_up(int root)
{
sum[root] = sum[root << 1] + sum[root << 1 | 1];
}

void build(int left, int right, int root)
{
if(left == right)
{
scanf("%d", &sum[root]);
return;
}
int mid = (left + right) >> 1;
build(lc);
build(rc);
push_up(root);
}
void update(int left, int right,
4000
int root, int a, int b)
{
if(left == right)
{
sum[root] += b;
return;
}
int mid = (left + right) >> 1;
if(a <= mid) update(lc, a, b);
else update(rc, a, b);
push_up(root);
}
int query(int left, int right, int root, int a, int b)
{
if(a <= left && right <= b)
{
return sum[root];
}
int mid = (left + right) >> 1;
int ans = 0;
if(b <= mid) ans += query(lc, a, b);
else if(a > mid) ans += query(rc, a, b);
else
{
ans += query(lc, a, b);
ans += query(rc, a, b);
}
return ans;
}
int main()
{
int t, n, m, a, b, cas = 0;
scanf("%d", &t);
while(t --)
{
printf("Case %d:\n", ++ cas);
scanf("%d", &n);
build(1, n, 1);
while(1)
{
char c[55];
scanf("%s", c);
if(!strcmp(c, "End")) break;
scanf("%d%d", &a, &b);
if(!strcmp(c, "Add"))
{
update(1, n, 1, a, b);
}
else if(!strcmp(c, "Sub"))
{
update(1, n, 1, a, -b);
}
else
{
int ans = query(1, n, 1, a, b);
printf("%d\n",ans);
}
}

}
return 0;
}