Submission #548630

#	Time	Username	Problem	Language	Result	Execution time	Memory
548630		Amylopectin	Three Friends (BOI14_friends)	C++14	100 / 100	63 ms	4704 KiB

friends

#include <iostream>
#include <stdio.h>

using namespace std;
const int mxn = 2e6 + 10;
char s[mxn] = {};
int let[31] = {};
int main()
{
    int i,j,n,m,odd,cou = 0,cl,cr,ans[2] = {},of;
    scanf("%d %s",&n,&s);
    for(i=0; i<n; i++)
    {
        let[s[i] - 'A'] ++;
    }
    for(i=0; i<26; i++)
    {
        if(let[i] % 2 == 1)
        {
            cou ++;
            odd = i;
        }
    }
    if(cou != 1 || n % 2 == 0)
    {
        printf("NOT POSSIBLE\n");
        return 0;
    }
    cl = 0;
    cr = n/2;
    for(j=0; j<2; j++)
    {
        if(j == 1)
        {
            cl = 0;
            cr = n/2 + 1;
        }
        of = 0;
        for(i=0; i<n/2; i++)
        {
            if(s[cl] != s[cr])
            {
                of ++;
                if(of > 1)
                {
                    break;
                }
                if(j == 0)
                {
//                    if(s[cr] - 'A' != odd)
//                    {
//                        of = 2;
//                        break;
//                    }
                    cr ++;
                }
                else
                {
//                    if(s[cl] - 'A' != odd)
//                    {
//                        of = 2;
//                        break;
//                    }
                    cl ++;
                }
                i--;
            }
            else
            {
                cl ++;
                cr ++;
            }
        }
        if(of >= 2)
        {
            ans[j] = -1;
        }
        else
            ans[j] = 1;
    }
    if(ans[0] == 1)
    {
        if(ans[1] == 1)
        {
            of = 0;
            for(i=0; i<n/2; i++)
            {
                if(s[i] != s[i+n/2+1])
                {
                    of = 1;
                    break;
                }
            }
            if(of == 1)
                printf("NOT UNIQUE\n");
            else
            {
                for(i=0; i<n/2; i++)
                {
                    printf("%c",s[i]);
                }
                printf("\n");
            }
        }
        else
        {
            for(i=0; i<n/2; i++)
            {
                printf("%c",s[i]);
            }
            printf("\n");
        }
    }
    else
    {
        if(ans[1] == 1)
        {
            for(i=n/2+1; i<n; i++)
            {
                printf("%c",s[i]);
            }
            printf("\n");
        }
        else
        {
            printf("NOT POSSIBLE\n");
        }
    }
    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'int main()':
friends.cpp:11:16: warning: format '%s' expects argument of type 'char*', but argument 3 has type 'char (*)[2000010]' [-Wformat=]
   11 |     scanf("%d %s",&n,&s);
      |               ~^     ~~
      |                |     |
      |                char* char (*)[2000010]
friends.cpp:10:15: warning: unused variable 'm' [-Wunused-variable]
   10 |     int i,j,n,m,odd,cou = 0,cl,cr,ans[2] = {},of;
      |               ^
friends.cpp:10:17: warning: variable 'odd' set but not used [-Wunused-but-set-variable]
   10 |     int i,j,n,m,odd,cou = 0,cl,cr,ans[2] = {},of;
      |                 ^~~
friends.cpp:11:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |     scanf("%d %s",&n,&s);
      |     ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 35 / 35
• Subtask 2: 65 / 65