Codeforces Round #303 (Div. 2) A B C D

题目链接：http://codeforces.com/contest/545

A：水
代码：

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <string>#include <queue>#include <set>using namespace std;int n, ans[110],tmp[21000],num;int p[110][110];int main(){    while (cin >> n)    {        set<int> q; q.clear();        num = 0;        for (int i = 1; i <= n; i++)            for (int j = 1; j <= n; j++)            {                scanf("%d", &p[i][j]);                 if (p[i][j] == -1)                {                    q.insert(i);                    q.insert(j);                }                else if (p[i][j] == 0)                {                    q.insert(i);                    q.insert(j);                }                else if (p[i][j] == 1)                {                    tmp[num++] = i;                    q.insert(j);                }                else if (p[i][j] == 2)                {                    tmp[num++] = j;                    q.insert(i);                }                else if (p[i][j] == 3)                {                    tmp[num++] = i;                    tmp[num++] = j;                }            }        for (int i = 0; i < num; i++)            q.erase(tmp[i]);        set<int> ::iterator it;        cout << q.size() << endl;        for (it = q.begin(); it != q.end(); it++)            cout << *it << " ";        cout << endl;    }    return 0;}

B: s ，t 字符不同的位置 ，奇数用s 偶数t，其他位置随意。

代码：

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <string>#include <queue>#include <set>using namespace std;char s[100010],t[100010];int ans[100010];int main(){    while (cin >> s >> t)    {        int len = strlen(s);        int tmp = 0;        memset(ans,0,sizeof(ans));        int num = 0;        for (int i = 0; i < len; i++)        {            if (s[i] != t[i])            {                tmp++;                ans[i] = -1;            }        }        if (tmp % 2 == 1)            puts("impossible");        else        {            for (int i = 0; i < len; i++)            {                if (ans[i] == -1)                {                    num++;                    if (num % 2 == 0) printf("%d", (s[i] - '0'));                    else  printf("%d", (t[i] - '0'));                }                else  printf("%d", (s[i] - '0'));            }            printf("\n");        }    }    return 0;}

C： 贪心直接搞

代码：

#include <vector>#include <string>#include <algorithm>#include <iostream>#include <stdio.h>using namespace std;const int MAXN=100010;int n;int dp[10010];struct node{    int x;    int y;    int left,right;}p[MAXN];bool cmp(node a,node b){    return a.x < b.x;}int main(){    while (cin>>n)    {        for(int i=1;i<=n;i++)        {            cin>>p[i].x>>p[i].y;            p[i].left = p[i].x - p[i].y;            p[i].right = p[i].x + p[i].y;        }        sort(p+1,p+1+n,cmp);        int ans=0;        int pos = -2000000000;        for(int i=1;i<=n;i++)        {            if (p[i].x - p[i].y > pos)            {                pos = p[i].x;                ans++;            }            else if (i == n || p[i].x + p[i].y < p[i+1].x)            {                pos = p[i].x + p[i].y;                ans++;            }            else                pos = p[i].x;        }        cout<<ans<<endl;    }    return 0;}

D： 排序直接搞 ，不满足条件直接不选。

代码：

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <string>#include <queue>#include <set>using namespace std;int n;int p[100010];int main(){    while (cin >> n)    {        for (int i = 1; i <= n; i++) cin >> p[i];        sort(p + 1, p + 1 + n);        long long tot = p[1];        int ans = 1;        for (int i = 2; i <= n; i++)        {            if (p[i] >= tot)            {                ans++;                tot += p[i];            }        }        printf("%d\n",ans);    }    return 0;}