Codeforces Round #205 (Div. 2)

A

 1 #include <iostream>

 2 #include<cstdio>

 3 #include<cstring>

 4 #include<algorithm>

 5 #include<stdlib.h>

 6 #include<vector>

 7 using namespace std;

 8 int a[110];

 9 int main()

10 {

11     int i,j,n,u,v;

12     int s1=0,s2=0,num=0;

13     scanf("%d",&n);

14     for(i = 1; i <= n ; i++)

15     {

16         scanf("%d%d",&u,&v);

17         if((u%2==0&&v%2!=0)||(u%2!=0&&v%2==0))

18         num++;

19         s1+=u;

20         s2+=v;

21     }

22     if(s1%2==0&&s2%2==0)

23     {

24         printf("0\n");

25     }

26     else if(s1%2!=0&&s2%2!=0)

27     {

28         if(num)

29         printf("1\n");

30         else

31         printf("-1\n");

32     }

33     else

34     printf("-1\n");

35     return 0;

36 }

View Code

B 构造一下。。乱弄了下

 1 #include <iostream>

 2 #include<cstdio>

 3 #include<cstring>

 4 #include<algorithm>

 5 #include<stdlib.h>

 6 #include<vector>

 7 using namespace std;

 8 #define N 210

 9 int n,a[N],f[N],o[N];

10 int main()

11 {

12     int i,j;

13     scanf("%d",&n);

14     for(i =1; i <= 2*n ; i++)

15     {

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

17         f[a[i]]++;

18     }

19     int s1=0,s2=0,num=0;

20     for(i = 10 ; i <= 99 ; i++)

21     if(f[i]>=2)

22     {

23         if(f[i]%2==0)

24         {

25             s1+=f[i]/2-1;

26         }

27         else

28         {

29             s1+=f[i]/2-1;

30             s2++;

31         }

32     }

33     else if(f[i]==1)

34     num++;

35     int k1 = s2/2,k2 = n-s1-s2/2;

36     int ans = (n-s1-s2/2)*(n-s1-(s2-s2/2));

37     num = (num+1)/2;

38    // printf("")

39     for(i = 1 ; i <= 2*n ; i++)

40     {

41         if(f[a[i]]==1)

42         {

43             o[i] = 1;

44             num--;

45         }

46         if(num==0)

47         break;

48     }

49     for(i = 1; i <= 2*n ; i++)

50     {

51         if(f[a[i]]>=2)

52         {

53             int kk;

54             if(k1&&f[a[i]]%2!=0)

55             {

56                 kk = f[a[i]]/2+1;

57                 k1--;

58             }

59             else

60             kk = f[a[i]]/2;

61             for(j = 1; j <= 2*n ; j++)

62             {

63                 if(a[j]==a[i])

64                 {

65                     kk--;

66                     o[j] = 1;

67                 }

68                 if(kk==0)

69                 break;

70             }

71             f[a[i]] = 0;

72         }

73     }

74     printf("%d\n",ans);

75     for(i = 1; i < 2*n ; i++)

76     if(o[i]==1)

77     printf("1 ");

78     else

79     printf("2 ");

80     if(o[2*n]==1)

81     printf("1\n");

82     else

83     printf("2\n");

84     return 0;

85 }

View Code

C  枚举1的位置 变为0后 后面全取1  一个很2的错误WA了2 次

 1 #include <iostream>

 2 #include<cstdio>

 3 #include<cstring>

 4 #include<algorithm>

 5 #include<stdlib.h>

 6 #include<vector>

 7 using namespace std;

 8 #define N 100010

 9 #define LL __int64

10 int a[N];

11 LL sum[N];

12 char s[N];

13 int main()

14 {

15     int i,j,n;

16     scanf("%d",&n);

17     for(i = 0; i < n ; i++)

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

19     cin>>s;

20     int k=-1;

21     LL ss=0,maxz=0;

22     for(i = 0 ; i < n ;i++)

23     {

24         if(s[i]=='1')

25         {

26             ss+=a[i];

27             if(i==0)

28             sum[i] = a[i];

29             else

30             sum[i]=sum[i-1]+a[i];

31             k = i;

32         }

33         else

34         if(i!=0)

35         sum[i] = sum[i-1];

36     }

37     if(k==-1)

38     printf("0\n");

39     else

40     {

41         maxz = max(maxz,ss);

42         int tsum=0;

43         for(i = 0 ; i <= k ; i++)

44         {

45             if(s[i]=='1')

46             {

47                 maxz = max(sum[k]-sum[i]+tsum,maxz);

48             }

49             tsum+=a[i];

50         }

51         printf("%I64d\n",maxz);

52     }

53     return 0;

54 }

View Code