学习杭电大牛的线段树风格

#include <cstdio>#include <algorithm>using namespace std; #define lson l , m , rt << 1#define rson m + 1 , r , rt << 1 | 1const int maxn = 111111;int h , w , n;int col[maxn<<2];int sum[maxn<<2];void PushUp(int rt) {sum[rt] = sum[rt<<1] + sum[rt<<1|1];}void PushDown(int rt,int m) {if (col[rt]) {col[rt<<1] = col[rt<<1|1] = col[rt];sum[rt<<1] = (m - (m >> 1)) * col[rt];sum[rt<<1|1] = (m >> 1) * col[rt];col[rt] = 0;}}void build(int l,int r,int rt) {col[rt] = 0;sum[rt] = 1;if (l == r) 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] = c * (r - l + 1);return ;}PushDown(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);PushUp(rt);}int main() {int T , n , m;scanf("%d",&T);for (int cas = 1 ; cas <= T ; cas ++) {scanf("%d%d",&n,&m);build(1 , n , 1);while (m --) {int a , b , c;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;}