poj 2777 Count Color
http://poj.org/problem?id=2777
简单线段树,【成段更新,成段查询】!
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 #include <algorithm> 5 6 using namespace std; 7 8 #define lson l, m, rt << 1 9 #define rson m + 1, r, rt << 1 | 1 10 11 const int maxn = 100001; 12 int color[maxn << 2], late[maxn << 2]; 13 14 void up(int rt) { 15 color[rt] = color[rt << 1] | color[rt << 1 | 1]; 16 } 17 18 void down(int rt) { 19 int l = rt << 1, r = rt << 1 | 1; 20 21 if (late[rt]) { 22 late[l] = late[r] = late[rt]; 23 color[l] = color[r] = late[rt]; 24 late[rt] = 0; 25 } 26 } 27 28 void build(int l, int r, int rt) { 29 late[rt] = 0; 30 if (l == r) { 31 color[rt] = 2; 32 33 return ; 34 } 35 int m = (l + r) >> 1; 36 37 build(lson); 38 build(rson); 39 up(rt); 40 } 41 42 void update(int key, int L, int R, int l, int r, int rt) { 43 if (L <= l && r <= R) { 44 color[rt] = late[rt] = 1 << key; 45 46 return ; 47 } 48 int m = (l + r) >> 1; 49 50 down(rt); 51 if (L <= m) update(key, L, R, lson); 52 if (m < R) update(key, L, R, rson); 53 up(rt); 54 } 55 56 int query(int L, int R, int l, int r, int rt) { 57 if (L <= l && r <= R) { 58 return color[rt]; 59 } 60 int m = (l + r) >> 1; 61 int ret = 0; 62 63 down(rt); 64 if (L <= m) ret |= query(L, R, lson); 65 if (m < R) ret |= query(L, R, rson); 66 up(rt); 67 68 return ret; 69 } 70 71 int main() { 72 int l, t, o; 73 int a, b, c; 74 char op[3]; 75 76 freopen("in", "r", stdin); 77 while (~scanf("%d%d%d", &l, &t, &o)) { 78 build(1, l, 1); 79 while (o--) { 80 scanf("%s", op); 81 switch (op[0]) { 82 case 'C': 83 scanf("%d%d%d", &a, &b, &c); 84 if (a > b) { 85 a ^= b; 86 b ^= a; 87 a ^= b; 88 } 89 update(c, a, b, 1, l, 1); 90 91 break; 92 case 'P': 93 scanf("%d%d", &a, &b); 94 if (a > b) { 95 a ^= b; 96 b ^= a; 97 a ^= b; 98 } 99 c = query(a, b, 1, l, 1); 100 101 int cnt = 0; 102 103 while (c) { 104 cnt += c & 1; 105 c >>= 1; 106 } 107 printf("%d\n", cnt); 108 109 break; 110 } 111 } 112 } 113 114 return 0; 115 }
——written by Lyon