[POJ] 3320 Jessica's Reading Problem (尺取法)

题目地址：http://poj.org/problem?id=3320

 1 #include<cstdio>

 2 #include<iostream>

 3 #include<string.h>

 4 #include<algorithm>

 5 #include<math.h>

 6 #include<stdbool.h>

 7 #include<time.h>

 8 #include<stdlib.h>

 9 #include<set>

10 #include<map>

11 #include<stack>

12 #include<queue>

13 #include<vector>

14 using namespace std;

15 #define clr(x,y)    memset(x,y,sizeof(x))

16 #define sqr(x)      ((x)*(x))

17 #define rep(i,a,b)  for(int i=(a);i<=(b);i++)

18 #define LL          long long

19 #define INF         0x3f3f3f3f

20 #define A           first

21 #define B           second

22 const int N=1e6+131;

23 int n,p,a[N];

24 

25 void solve()

26 {

27     set<int>all;

28     map<int,int>count;

29     

30     scanf("%d",&p);

31     for(int i=0;i<p;i++) {

32         scanf("%d",&a[i]);

33         all.insert(a[i]);

34     }

35     n=all.size();

36     

37     int lb=0,ub=0,num=0;

38     int res=p;

39     while(true) {

40         while(ub<p && num<n) {

41             if(count[a[ub++]]++ == 0)

42             num++;

43         }

44         if(num<n) break;

45         res=min(res,ub-lb);

46         if(--count[a[lb++]]==0) {

47             num--;

48         }

49     }

50     

51     printf("%d\n",res);

52     

53 }

54 int main()

55 {

56     solve();

57     return 0;

58 }