CF652 前两题

额，这次比赛就打了一个小时吧，因为寝室要关门了，没时间打了。不过感觉就算打下去我估计也是就做出两题吧。第三题确实不会。

http://codeforces.com/contest/652/problem/C

第一题的话就是分类讨论一下就出来了。如果b>a的话就讨论第一天和第二天的。不然就只需要单纯讨论第一天就可以了

#include<cstdio>#include<algorithm>#include<cstring>#include<cmath>#include<queue>#include<stack>#include<map>using namespace std;typedef long long ll;const ll inf = 0x3f3f3f3f;const int ti = 14;const int night = 22;const int day = 10;int h1, h2;int a, b;int main(){while (scanf("%d%d", &h1, &h2) == 2){ scanf("%d%d", &a, &b); ll cnt = 0; h1 = h1 + a * (night - ti); if (h1 >= h2) { printf("%I64d\n", cnt); continue; } h1 = h1 - 12 * b; h1 = h1 + 12 * a; cnt++; if (h1 > h2){ printf("%I64d\n", cnt); continue; } else if(h1 < h2 && a <= b){ printf("-1\n"); continue; } while (h1 < h2){ h1 -= b * 12; h1 += a * 12; cnt++; } printf("%I64d\n", cnt);}return 0;}</map></stack></queue></cmath></cstring></algorithm></cstdio>

第二题看了好大牛的想法都是sort以后从两端枚举。不过我的想法有点不同。我是sort以后然后从开头枚举，然后到偶数的时候就swap一下就好了。（ma~，说到底想法都差不多吧）

#include<cstdio>#include<algorithm>#include<cstring>#include<cmath>#include<queue>#include<stack>#include<map>using namespace std;typedef long long ll;const ll inf = 0x3f3f3f3f;int n;const int maxn = 1000 + 5;ll a[maxn];int main(){while (scanf("%d", &n) == 1){ memset(a, 0, sizeof(a)); for (int i = 1; i <= n; i++) scanf("%I64d", a + i); sort(a + 1, a + 1 + n); for (int i = 1; i < n; i++){ if (i % 2 == 0 && a[i] < a[i + 1]){ swap(a[i], a[i + 1]); } } for (int i = 1; i <= n; i++){ printf("%I64d%c", a[i], i == n? '\n' : ' '); }}return 0;}</map></stack></queue></cmath></cstring></algorithm></cstdio>