线段树+区间离散化：弄了好久，注意数组范围。
1 #include<stdio.h> 2 #include<string.h> 3 #include<stdlib.h> 4 #define MAXN 10000+100 5 6 int T, n, a[MAXN<<2], b[MAXN<<2], r[MAXN<<2], h[MAXN<<2], to[MAXN<<4]; 7 8 int cmp(const void *_p, const void *_q) 9 { 10 int *p = (int *)_p; 11 int *q = (int *)_q; 12 return a[*p]-a[*q]; 13 } 14 15 void build(int cur,int x, int y) 16 { 17 int mid = (x+y)>>1, ls = cur<<1, rs = cur<<1|1; 18 to[cur] = -1; 19 if(x == y) return; 20 build(ls, x, mid); 21 build(rs, mid+1, y); 22 } 23 24 void pushdown(int cur) 25 { 26 int ls = cur<<1, rs = cur<<1|1; 27 if(to[cur] != -1) 28 { 29 to[ls] = to[rs] = to[cur]; 30 to[cur] = -1; 31 } 32 } 33 34 void color(int cur, int x, int y, int s, int t, int v) 35 { 36 int mid = (x+y)>>1, ls = cur<<1, rs = cur<<1|1; 37 if(x>=s && y<=t) 38 { 39 to[cur] = v; 40 return ; 41 } 42 pushdown(cur); 43 if(mid>=s) 44 color(ls, x, mid, s, t, v); 45 if(mid+1<=t) 46 color(rs, mid+1, y, s, t, v); 47 } 48 49 void search(int cur, int x, int y, int &ans) 50 { 51 int mid = (x+y)>>1, ls = cur<<1, rs = cur<<1|1; 52 if(to[cur] != -1) 53 { 54 if(!h[to[cur]]) 55 { 56 ans++;//printf("cur=%d\n",cur); 57 h[to[cur]] = 1; 58 } 59 return ; 60 } 61 if(x == y) return ; 62 search(ls, x, mid, ans); 63 search(rs, mid+1, y, ans); 64 } 65 66 void init() 67 { 68 while(~scanf("%d",&T)) 69 while(T--) 70 { 71 scanf("%d",&n); 72 for(int i = 1; i <= n*2; i ++) 73 { 74 scanf("%d",&a[i]); 75 } 76 for(int i = 0; i <= n*2; i ++) 77 r[i] = i; 78 a[0] = -1; 79 qsort(r+1, 2*n, sizeof(r[0]), cmp);//for(int i = 0; i <=2*n; i ++)printf("a[r[i]]=%d\n",a[r[i]]);puts(""); 80 int p = 0; 81 for(int i = 1; i <= 2*n; i ++) 82 {//printf("a[r[i-1]]=%d a[r[i]]=%d\n",a[r[i-1]], a[r[i]]); 83 if(a[r[i]]-a[r[i-1]] >= 1) {p += 1;b[r[i]] = p;} 84 //else if(a[r[i]]-a[r[i-1]] > 1){p += 2; b[r[i]] = p;} 85 else b[r[i]] = b[r[i-1]]; 86 }//for(int i = 0; i <=2*n; i ++)printf("a[r[i]]=%d\n",b[r[i]]); 87 build(1,1,p); 88 int v = 0; 89 for(int i = 1; i <= 2*n; i += 2) 90 { 91 v ++;//printf("b[i]=%d b[i+1]=%d\n",b[i],b[i+1]); 92 color(1, 1, p, b[i], b[i+1], v); 93 }//for(int i = 0; i < 30; i ++) printf("i=%d to[i]=%d\n",i,to[i]); 94 int ans = 0; 95 memset(h, 0, sizeof(h[0])*(v+10)); 96 search(1, 1, p, ans); 97 printf("%d\n",ans); 98 } 99 } 100 int main() 101 { 102 init(); 103 return 0; 104 }