线段树。各种WA。最后过了，老泪纵横。
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1 #include <stdio.h> 2 #define MAXN 100001 3 int col[MAXN * 4],lazy[MAXN * 4]; 4 void update(int cur) 5 { 6 col[cur] = col[cur << 1] | col[cur << 1 | 1]; 7 } 8 9 void pushdown(int cur,int x,int y) 10 { 11 int mid = (x + y) >> 1,ls = cur << 1,rs = cur << 1 | 1; 12 if(lazy[cur] != -1) 13 { 14 lazy[ls] = lazy[cur]; 15 lazy[rs] = lazy[cur]; 16 col[ls] = lazy[cur]; 17 col[rs] = lazy[cur]; 18 lazy[cur] = -1; 19 } 20 } 21 22 void build(int cur,int x,int y) 23 { 24 int mid = (x + y) >> 1,ls = cur << 1,rs = cur << 1 | 1; 25 lazy[cur] = -1; 26 if(x == y) 27 { 28 col[cur] = 1; 29 return; 30 } 31 build(ls,x,mid); 32 build(rs,mid + 1,y); 33 update(cur); 34 } 35 36 void change(int cur,int x,int y,int s,int t,int c) 37 { 38 int mid = (x + y) >> 1,ls = cur << 1,rs = cur << 1 | 1; 39 if(x >= s && y <= t) 40 { 41 col[cur] = c; 42 lazy[cur] = c; 43 return; 44 } 45 pushdown(cur,x,y); 46 if(mid >= s) 47 change(ls,x,mid,s,t,c); 48 if(mid + 1 <= t) 49 change(rs,mid + 1,y,s,t,c); 50 update(cur); 51 } 52 53 void query(int cur,int x,int y,int s,int t,int &ans) 54 { 55 int mid = (x + y) >> 1,ls = cur << 1,rs = cur << 1 | 1; 56 57 if(x >= s && y <= t) 58 { 59 ans |= col[cur]; 60 return; 61 } 62 pushdown(cur,x,y); 63 if(mid >= s) 64 query(ls,x,mid,s,t,ans); 65 if(mid + 1 <= t) 66 query(rs,mid + 1,y,s,t,ans); 67 //update(cur); 68 } 69 70 int cal(int a) 71 { 72 int ans = 0; 73 while(a) 74 { 75 if(a % 2) 76 ans++; 77 a >>= 1; 78 } 79 return ans; 80 } 81 82 int main() 83 { 84 int L,O,T,a,b,c,ans,temp; 85 char ch; 86 while(scanf("%d%d%d",&L,&T,&O) == 3) 87 { 88 build(1,1,L); 89 while(O--) 90 { 91 /*printf("\n"); 92 for(int i = 0;i <= L * 4;i++) 93 printf("%d ",col[i]); 94 printf("\n");*/ 95 getchar(); 96 scanf("%c",&ch); 97 if(ch == 'C') 98 { 99 scanf("%d%d%d",&a,&b,&c); 100 if(a > b) 101 { 102 temp = a; 103 a = b; 104 b = temp; 105 } 106 change(1,1,L,a,b,1 << (c - 1)); 107 } 108 else 109 { 110 scanf("%d%d",&a,&b); 111 if(a > b) 112 { 113 temp = a; 114 a = b; 115 b = temp; 116 } 117 ans = 0; 118 query(1,1,L,a,b,ans); 119 printf("%d\n",cal(ans)); 120 } 121 /*printf("\n"); 122 for(int i = 0;i <= L * 4;i++) 123 printf("%d ",col[i]); 124 printf("\n"); 125 for(int i = 0;i <= L * 4;i++) 126 printf("%d ",lazy[i]); 127 printf("\n");*/ 128 } 129 } 130 return 0; 131 }