Codeforces Round #313 (Div. 2) ABC

A
http://codeforces.com/contest/560/problem/A
推断给出的数能否组成全部自然数。

水题

int a[1010];
bool b[1000010];

int main()
{
    int n;
    while (scanf("%d", &n) != EOF)
    {
        memset(b,false,sizeof(b));
        for (int i = 1; i <= n; i++)
        {
            scanf("%d", &a[i]);
            b[a[i]] = true;
        }
        int ans = 0;
        if (b[1] == false) ans = 1;
        else if (b[1]) ans = -1;

        printf("%d
",ans);
    }
    return 0;
}

B
http://codeforces.com/contest/560/problem/B
推断一个矩形能否装下另外两个矩形

int a1, a2, a3, b1, b2, b3;

int main()
{
    while (scanf("%d%d%d%d%d%d", &a1, &b1, &a2, &b2, &a3, &b3) != EOF)
    {
        int ok = 0;

        int t1 = max(b2, b3);
        int r1 = max(a2, a3);

        if ((t1 <= a1 && (a2 + a3) <= b1)) ok = 1;
        if ((t1 <= b1 && (a2 + a3) <= a1)) ok = 1;
        if ((r1 <= a1 && (b2 + b3) <= b1)) ok = 1;
        if ((r1 <= b1 && (b2 + b3) <= a1)) ok = 1;

        int t11 = max(b2, a3);
        int r11 = max(a2, b3);

        if ((r11 <= a1 && (b2 + a3) <= b1)) ok = 1;
        if ((r11 <= b1 && (b2 + a3) <= a1)) ok = 1;
        if ((t11 <= a1 && (a2 + b3) <= b1)) ok = 1;
        if ((t11 <= b1 && (a2 + b3) <= a1)) ok = 1;

        if (ok) puts("YES");
        else puts("NO");
    }
    return 0;
}

C
http://codeforces.com/contest/560/problem/C
推断组成六边形须要的三角形个数

int a, b, c, d, e, f;

int main()
{
    while (scanf("%d%d%d%d%d%d", &a, &b, &c, &d, &e, &f) != EOF)
    {
        printf("%d
", (a + b + c)*(a + b + c) - (a*a + c*c + e*e));
    }
    return 0;
}