你们猜为什么，怎么改？

#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
//#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>

using namespace std;

#define MAXN 400010
long long addv[MAXN];
long long sumv[MAXN];

int y1, y2;

void maintain(int o, int L, int R) {
    int lc = o*2, rc = o*2+1;
    if (R > L) {
        sumv[o] = sumv[lc] + sumv[rc];
    }
    sumv[o] += addv[o] * (R-L+1);
    if (R == L) addv[o] = 0;
}


int v;
void update(int o, int L, int R) {
    int lc = o*2, rc = o*2+1;
    if (y1 <= L && R <= y2) {
        addv[o] += v;
    } else {
        int M = L + (R-L)/2;
        if (y1 <= M) update(lc, L, M);
        if (y2 > M) update(rc, M+1, R);
    }
    maintain(o, L, R);
}

long long _sum;
void query(int o, int L, int R, long long add) {
    if (y1 <= L && R <= y2) {
        _sum += sumv[o] + add * (R-L+1);
    } else {
        int M = L + (R-L)/2;
        if (y1 <= M) query(o*2, L, M, add + addv[o]);
        if (y2 > M) query(o*2+1, M+1, R, add + addv[o]);
    }
}

int main()
{
    int N, M;
    cin >> N >> M;
    for (int i = 1; i <= N; ++i) {
        scanf("%d", &v);
        y1 = y2 = i;
        update(1, 1, N);
    }
    memset(addv, 0, sizeof addv);
    for (int i = 0; i != M; ++i) {
        char C;
        int A, B;
        getchar();
        scanf("%c%d%d", &C, &A, &B);
        switch(C) {
        case 'Q':
            y1 = A; y2 = B;
            _sum = 0;
            query(1, 1, N, 0);
            printf("%I64d\n", _sum);
            break;
        case 'C':
            scanf("%d", &v);
            y1 = A; y2 = B;
            update(1, 1, N);
        }
    }

    return 0;
}