题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1698
通过这个题练习了基本的Pushdown的操作
参考着蓝书的模板敲了一下，需要修改的地方就是：这里的区间修改是直接改变值而不是增加值
把+=改成=即可。
1 #include <cmath> 2 #include <queue> 3 #include <string> 4 #include <cstdio> 5 #include <cstring> 6 #include <iostream> 7 #include <algorithm> 8 #define forn(i, n) for (int i = 0; i < (n); i++) 9 #define forab(i, a, b) for (int i = (a); i <= (b); i++) 10 #define forba(i, b, a) for (int i = (b); i >= (a); i--) 11 #define mset(a, n) memset(a, n, sizeof(a)) 12 #define fast ios::sync_with_stdio(0), cin.tie(0), cout.tie(0) 13 #define P pair<int,int> 14 #define fi first 15 #define se second 16 using namespace std; 17 #define N 100005 18 #define inf 0x3f3f3f3f 19 #define ll long long 20 struct SegmentTree 21 { 22 int l, r; 23 ll data; 24 ll add; 25 #define l(x) t[x].l 26 #define r(x) t[x].r 27 #define data(x) t[x].data 28 #define add(x) t[x].add 29 } t[N * 4 + 5]; 30 ll n, m, cnt; 31 void build(int p,int l,int r) 32 { 33 l(p) = l; 34 r(p) = r; 35 add(p) = 0; 36 if(l==r) 37 { 38 data(p) = 1; 39 return; 40 } 41 int m = (l + r) / 2; 42 int ls = 2 * p, rs = 2 * p + 1; 43 build(ls, l, m); 44 build(rs, m + 1, r); 45 data(p) = data(ls) + data(rs); 46 } 47 void spread(int p) 48 { 49 if(add(p)) 50 { 51 data(2 * p) = add(p) * (r(2 * p) - l(2 * p) + 1); 52 data(2 * p + 1) = add(p) * (r(2 * p + 1) - l(2 * p + 1) + 1); 53 add(2 * p) = add(p); 54 add(2 * p + 1) = add(p); 55 add(p) = 0; 56 } 57 } 58 void change(int p,int l,int r,int d) 59 { 60 if(l<=l(p)&&r>=r(p)) 61 { 62 data(p) = (r(p) - l(p) + 1) * d; 63 add(p) = d; 64 return; 65 } 66 spread(p); 67 int m = (l(p) + r(p)) / 2; 68 int ls = 2 * p, rs = 2 * p + 1; 69 if(l<=m) 70 change(ls, l, r, d); 71 if(r>m) 72 change(rs, l, r, d); 73 data(p) = data(ls) + data(rs); 74 } 75 int main() 76 { 77 fast; 78 cin >> cnt; 79 forab(cas,1,cnt) 80 { 81 cin >> n >> m; 82 build(1, 1, n); 83 forab(i,1,m) 84 { 85 int x, y, z; 86 cin >> x >> y >> z; 87 change(1, x, y, z); 88 } 89 cout << "Case " << cas << ": The total value of the hook is " <<t[1].data<< "." << endl; 90 } 91 } 92 /* 93 1 94 10 95 2 96 1 5 2 97 5 9 3 98 */