Codeforces Round #200 (Div. 2)

My submissions

 

 

#WhenWhoProblemLangVerdictTimeMemory446735101:27:52hybestD - Alternating CurrentGNU C++Accepted30 ms344 KB446544001:05:14hybestC - Rational ResistanceGNU C++Accepted30 ms0 KB446467600:58:40hybestC - Rational ResistanceGNU C++Runtime error on pretest 50 ms0 KB446392300:45:45hybestC - Rational ResistanceGNU C++Runtime error on pretest 530 ms0 KB446171900:23:13hybestB - Simple MoleculesGNU C++Accepted30 ms0 KB446007400:10:23hybestA - MagnetsGNU C++Accepted62 ms0 KB445979200:08:45hybestA - MagnetsGNU CCompilation error0 ms0 KB

8分钟的时候交A题，编译器选错了，然后刷新又得等好久……

C题RE的原因是输入b为1的情况，会有除0的操作，竟然用了20分钟才发现这个问题……

A题代码

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<string>#include<stack>#include<map>#include<queue>#include<algorithm>using namespace std;int main(){    int n, a, b, res = 0;    a = 0 - 1;    scanf("%d", &n);    while( n-- )    {        b = a;        scanf("%d", &a);        if( a != b)        {            res++;        }    }    printf("%d\n", res);    return 0;}

B题代码

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<string>#include<stack>#include<map>#include<queue>#include<algorithm>using namespace std;int main(){int a, b, c;int aa, bb, cc;scanf("%d %d %d", &a, &b, &c);aa = (b - c + a ) / 2;bb = (c - a + b ) / 2;cc = (a - b + c ) / 2;if( (aa + bb != b) || (bb + cc != c) || (cc + aa != a) || aa < 0 || bb  < 0 || cc < 0){printf("Impossible\n");return 0;}printf("%d %d %d", aa, bb, cc);return 0;}

C题代码

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<string>#include<stack>#include<map>#include<queue>#include<algorithm>using namespace std;int main(){__int64 a, b, res = 0, temp;scanf("%I64d %I64d", &a, &b);if(a == b){printf("1\n");return 0;}if( b == 1){printf("%I64d\n", a);return 0;}res += a / b;a %= b;while( a != 1 ){res += b / a;temp = b;b = a;a = temp;a = a % b;}res += b;printf("%I64d\n", res);return 0;}

D题代码

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<string>#include<stack>#include<map>#include<queue>#include<algorithm>using namespace std;char str[100050];int main(){    stack<char>a;    scanf("%s", str);    int i, l;    l = strlen(str);    if( l % 2)    {        printf("No\n");        return 0;    }    a.push(str[0]);    for( i = 1; i < l; i++)    {        if( a.empty() || str[i] != a.top() )        {            a.push(str[i]);        }        else        {            a.pop();        }    }    if( a.empty())    {        printf("Yes\n");        return 0;    }    else    {        printf("No\n");    }    return 0;}

题目都太水了，好多人半小时左右就过了四个题目的……

解体报告就懒得写了，这种题目一看代码就能懂的吧。