poj 2528 Mayor's posters

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 }