POJ - 3468 A Simple Problem with Integers(区间修改，区间查询，模板题)

​​POJ - 3468 A Simple Problem with Integers​​

题目

线段树裸题

分析

模板，注意下注释部分，累加变量要用long long

#include <cstdio>
#include <iostream>
#include <cstring>
#include <cmath>
#include <algorithm>
#define INF 0x3f3f3f3f
#define d(x) cout << (x) << endl
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1

// #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 9999991;
const int N = 1e5 + 10;

int n, q, x, y;
char c[10];
ll tr[N << 2], col[N << 2];

void pushup(int rt){
    tr[rt] = tr[rt << 1] + tr[rt << 1 | 1];
}

void pushdown(int rt, int m){
    ll c = col[rt];
    if(c){
        col[rt << 1] += c;
        col[rt << 1 | 1] += c;
        tr[rt << 1] += c * (m - (m >> 1));      //注意左右区间长度
        tr[rt << 1 | 1] += c * (m >> 1);
        col[rt] = 0;
    }
}

void build(int l, int r, int rt){
    if(l == r){
        scanf("%lld", &tr[rt]);           //注意是 tr[rt] 不是 tr[l]
        return;
    }
    int m = l + r >> 1;
    build(lson);
    build(rson);
    pushup(rt);
}

void update(int l, int r, int rt, int L, int R, ll add){
    if(L <= l && r <= R){
        tr[rt] += (r - l + 1) * add;
        col[rt] += add;             
        return;
    }
    pushdown(rt, r - l + 1);        //每次用到左右儿子都要下放懒惰标记
    int m = l + r >> 1;
    if(L <= m){
        update(lson, L, R, add);
    }
    if(m < R){
        update(rson, L, R, add);
    }
    pushup(rt);
}

ll query(int l, int r, int rt, int L, int R){
    if(L <= l && r <= R){
        return tr[rt];
    }
    ll ans = 0;
    int m = l + r >> 1;
    pushdown(rt, r - l + 1);
    if(L <= m){
        ans += query(lson, L, R);
    }
    if(m < R){
        ans += query(rson, L, R);
    }
    return ans;
}

int main()
{
    scanf("%d%d", &n, &q);
    build(1, n, 1);
    while(q--){
        scanf("%s%d%d", &c, &x, &y);
        if(c[0] == 'C'){
            ll add;
            scanf("%lld", &add);
            update(1, n, 1, x, y, add);
        }else{
            printf("%lld\n", query(1, n, 1, x, y));
        }
    }
    return 0;
}

/*
10 5
1 2 3 4 5 6 7 8 9 10
C 3 6 3
Q 2 4

*/