POJ 3468 A Simple Problem with Integers 线段树成段更新

Posted 2020-10-04 Pacify

线段树功能 　

update：成段更新  query：区间求和

#include <iostream>
#include <string>
#include <cstdio>
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
using namespace std;

typedef long long ll;
const int MAXN = 111111;
ll sum[MAXN<<2], add[MAXN<<2];

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

void push_down(int rt, int len)
{
    if(add[rt] == 0) return;
    add[rt<<1] += add[rt];
    add[rt<<1|1] += add[rt];
    sum[rt<<1] += (len - (len >> 1)) * add[rt];
    sum[rt<<1|1] += (len >> 1) * add[rt];
    add[rt] = 0;
}

void build(int l, int r, int rt)
{
    add[rt] = 0;
    if(l == r)
    {
        scanf("%I64d", &sum[rt]);
        return;
    }
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
    push_up(rt);
}

void update(int L, int R, int c, int l, int r, int rt)
{
    if(L <= l && r <= R)
    {
        sum[rt] += c * (r - l + 1);
        add[rt] += c;
        return;
    }
    push_down(rt, r-l+1);
    int m = (l + r) >> 1;
    if(L <= m) update(L, R, c, lson);
    if(R > m) update(L, R, c, rson);
    push_up(rt);
}

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

int main()
{
//    freopen("in.txt", "r" ,stdin);
    int N, Q;
    while(~scanf("%d%d", &N, &Q))
    {
        build(1, N, 1);
        while(Q--)
        {
            int a, b, c;
            char s[3];
            scanf("%s", s);
            scanf("%d%d", &a, &b);
            if(s[0] == ‘Q‘) printf("%I64d\n", query(a, b, 1, N, 1));
            else
            {
                scanf("%d", &c);
                update(a, b, c, 1, N, 1);
            }
        }
    }
    return 0;
}