Codeforces Round #306 (Div. 2) A B C

题目链接：http://codeforces.com/contest/550

A

暴力一发。

代码：

#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string>
#include <string.h>
#include <set>
#include <map>
#include <vector>
#include <algorithm>

using namespace std;

const int MAXN =100010;

char s[MAXN];
int pos1[MAXN];
int pos2[MAXN];

int main()
{
    while (cin>>s)
    {
        int ok1 = 0,ok2 = 0;
        int tmp = 0;
        int len = strlen(s);
        int num1 = 0,num2 = 0;

        for(int i = 0;i < len - 1;i++)
        {
            if (s[i] == 'A' && s[i+1]=='B')
            {
                ok1 = 1;
                pos1[num1++] = i;
            }
            if (s[i] == 'B' && s[i+1]=='A')
            {
                ok2 = 1;
                pos2[num2++] = i;
            }
        }
        int ok=0;
        if (ok1 == 1 && ok2 == 1)
        {
            for(int i=0;i < num1;i++)
            {
                if(ok) break;
                for(int j=0;j < num2;j++)
                {
                    if (abs(pos1[i] - pos2[j]) != 1)
                    {
                        ok=1;
                        break;
                    }
                }
            }
        }
        if (ok) puts("YES");
        else puts("NO");
    }
    return 0;
}

B 再暴力一发

#include <math.h>
#include <limits.h>
#include <complex>
#include <string>
#include <functional>
#include <iterator>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <list>
#include <bitset>
#include <sstream>
#include <iomanip>
#include <fstream>
#include <iostream>
#include <ctime>
#include <cmath>
#include <cstring>
#include <cstdio>
#include <time.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>

using namespace std;

int n, l, r, X, a[100];
int ans;

void rec(int x, int sum, int mn, int mx, int cnt)
{
    if (x == n)
    {
        if ((cnt >= 2) && (sum >= l) && (sum <= r) && (mx - mn >= X)) ans++;
        return;
    }
    rec(x + 1, sum, mn, mx, cnt);
    rec(x + 1, sum + a[x], min(mn, a[x]), max(mx, a[x]), cnt + 1);
}

int main() {

    while(~scanf("%d%d%d%d", &n, &l, &r, &X))
    {
        for (int i = 0; i < n; i++)
            scanf("%d", &a[i]);
        rec(0, 0, 1e9, -1e9, 0);
        printf("%d\n", ans);
    }
}

C 再再暴力一发

代码:

#include <math.h>
#include <limits.h>
#include <complex>
#include <string>
#include <functional>
#include <iterator>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <list>
#include <bitset>
#include <sstream>
#include <iomanip>
#include <fstream>
#include <iostream>
#include <ctime>
#include <cmath>
#include <cstring>
#include <cstdio>
#include <time.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>

using namespace std;

char s [1010];

void solve()
{
    int len = strlen(s);
    for(int i=0;i<len;i++)
    {
        if((s[i] - 48) % 8 == 0)
        {
            puts("YES");
            printf("%c\n",s[i]);
            return;
        }
    }
    for(int i=0;i<len;i++)
    {
        for(int j=i+1;j<len;j++)
        {
            int num = s[i] - 48;
            num = num *10 + s[j]-48;
            if (num % 8 == 0)
            {
                puts("YES");
                printf("%d\n",num);
                return;
            }
        }
    }
    for(int i=0;i<len;i++)
    {
        if (s[i] != '0')
            for(int j=i+1;j<len;j++)
                for(int k=j+1;k<len;k++)
                {
                    int num = s[i]-48;
                    num = num*10 + s[j] - 48;
                    num = num*10 + s[k] - 48;
                    if (num % 8 == 0)
                    {
                        puts("YES");
                        printf("%d\n",num);
                        return ;
                    }

                }

    }
    puts("NO");
}

int main()
{
    while (cin>>s)
    {
        int len = strlen(s);
        solve();
    }
    return 0;
}