线段树区间更新

Code:

//线段树的区间更新
#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
typedef long long  LL;
const int DAT_SIZE = (1 << 18) -1;
const int maxn = 100010;
int N, Q;
LL A[maxn];
char T[maxn];
int L[maxn], R[maxn], X[maxn];
LL data[DAT_SIZE], datb[DAT_SIZE];

void add(int a, int b, int x, int k, int l, int r) //给(a, b)区间的数字都加上x, (l, r)区间的标号是k
{
    if(a <= l && r <= b)                      //(a, b) 将 (l, r)包围
    {
        data[k] += x;
    }
    else if(l < b && a < r)
    {
        datb[k] += (min(b, r) - max(a, l)) * x;
        add(a, b, x, k*2+1, l, (l+r)/2);
        add(a, b, x, k*2+2, (l+r)/2, r);
    }
}

LL sum(int a, int b, int k, int l, int r)
{
    if(b <= l || r <= a)
        return 0;
    else if(a <= l && r <= b)
        return data[k] * (r-l) + datb[k];
    else {
        LL res = (min(b, r)-max(a, l)) * data[k];
        res += sum(a, b, k*2+1, l, (l+r)/2);
        res += sum(a, b, k*2+2, (l+r)/2, r);
        return res;
    }
}

int main()
{
    scanf("%d %d", &N, &Q);
    memset(data, 0, sizeof(data));
    memset(datb, 0, sizeof(datb));
    for(int i = 0; i < N; i++)
    {
        scanf("%lld", &A[i]);
        add(i, i+1, A[i], 0, 0, N);
    }

    while(Q--)
    { getchar();
        char op;
        int left, right, val;
        scanf("%c %d %d", &op, &left, &right);
        //cin >> op >> left >> right;
        if(op == 'C')
        {
            scanf("%d", &val);
            add(left-1, right, val, 0, 0, N);
        }
        else
        {
            cout << sum(left-1, right, 0, 0, N) << endl;
        }
    }
    return 0;
}