HDU 1698 Just a Hook（成段更新）

转载请注明出处：忆梦http://blog.csdn.net/yimeng2013/article/details/17191439

#include<cstdio>
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
#define maxn 111111

int sum[maxn<<2];
int col[maxn<<2];

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

void Pushdown(int rt, int len)
{
if(col[rt])
{
col[rt<<1] = col[rt<<1|1] = col[rt];
sum[rt<<1] = ( len - (len>>1) )* col[rt];
sum[rt<<1|1] = (len >> 1) * col[rt];
col[rt] = 0;
}
}
void build(int l, int r, int rt)
{
col[rt] = 0;
if(l == r)
{
sum[rt] = 1;
return ;
}

int m = (l + r) >> 1;
build(lson);
build(rson);
PushUp(rt);
}

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

int main ()
{
int T;
scanf("%d", &T);
for(int cas = 1; cas <= T; cas++)
{
int n, m;
scanf("%d %d", &n, &m);

build(1, n, 1);
int a, b, c;
while(m--)
{
scanf("%d %d %d", &a, &b, &c);
update(a, b, c, 1, n, 1);
}
printf("Case %d: The total value of the hook is %d.\n", cas, sum[1]);
}
return 0;
}