Poj3468 线段树 -- 成段更新

#include <stdio.h>

#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1

const int maxn = 100004;

char     cmd[2];
int      n, mNum, a, b, c;
__int64  sum[maxn<<2]={0}, col[maxn<<2]={0};

void BuildTree(int l, int r, int rt)
{
col[rt] = 0;
if (l == r)
{
scanf("%I64d", &sum[rt]);
return ;
}/* End of If */

int m = (l+r)>>1;
BuildTree(lson);
BuildTree(rson);
sum[rt] = sum[rt<<1] + sum[rt<<1|1];    /* Push Up */
}/* BuildTree */

void PushDown(int rt, int k)　　/* 延迟标志 */
{
if (col[rt])
{
col[rt<<1] += col[rt]; /* caution，因为col[rt]的更新出错，我WA了好多次 */
col[rt<<1|1] += col[rt];
sum[rt<<1] += col[rt]*(k-(k>>1));
sum[rt<<1|1] += col[rt]*(k>>1);
col[rt] = 0;
}
}/* PushDown */

__int64 Query(int L, int R, int l, int r, int rt)
{
if (L<=l && r<=R)
return sum[rt];

PushDown(rt, r-l+1);    /* Push down */

__int64 ret = 0;
int     m = (l+r)>>1;

if (L <= m)
ret += Query(L, R, lson);
if (R > m)
ret += Query(L, R, rson);

return ret;
}/* Query */

void UpData(int L, int R, int c, int l, int r, int rt)
{
if (L<=l && r<=R)
{
col[rt] += c;
sum[rt] += c*(r-l+1);

return ;
}/* End of If */

PushDown(rt, r-l+1);    /* Push down */

int m = (l+r)>>1;

if (L <= m)
UpData(L, R, c, lson);
if (R > m)
UpData(L, R, c, rson);
sum[rt] = sum[rt<<1] + sum[rt<<1|1];    /* Push Up */
}/* UpData */

int main()
{
scanf("%d %d", &n, &mNum);

BuildTree(1, n, 1);
for (int i=1; i<=mNum; ++i)
{
scanf("%s", cmd);
if (cmd[0] == 'Q')
{   /* Query */
scanf("%d %d", &a, &b);
printf("%I64d\n", Query(a, b, 1, n, 1));
}
else
{   /* Add */
scanf("%d %d %d", &a, &b, &c);
UpData(a, b, c, 1, n, 1);
}
}/* End of For */

return 0;
}