被进爷坑了，第二天的比赛改到了12点
/************************************************
* Author :Running_Time
* Created Time :2015/10/3 星期六 21:53:09
* File Name :A.cpp
************************************************/
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int N = 55;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const double EPS = 1e-8;
bool r[N], c[N];
int main(void) {
memset (r, false, sizeof (r));
memset (c, false, sizeof (c));
int n; scanf ("%d", &n);
vector<int> ans;
n = n * n;
for (int x, y, i=1; i<=n; ++i) {
scanf ("%d%d", &x, &y);
if (!r[x] && !c[y]) {
r[x] = c[y] = true;
ans.push_back (i);
}
}
for (int i=0; i<ans.size (); ++i) {
printf ("%d%c", ans[i], (i == ans.size () - 1) ? '
' : ' ');
}
return 0;
}
/************************************************
* Author :Running_Time
* Created Time :2015/10/3 星期六 21:53:24
* File Name :B.cpp
************************************************/
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int N = 1e3 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const double EPS = 1e-8;
int a[N];
int main(void) {
int n; scanf ("%d", &n);
for (int i=1; i<=n; ++i) {
scanf ("%d", &a[i]);
}
int ans = 0, d = 1, m = 0, p = 0;
bool flag = false;
while (true) {
if (d == 1) {
for (int i=p+1; i<=n; ++i) {
if (m >= a[i]) {
a[i] = INF;
m++; p = i;
flag = true;
}
}
if (m == n) break;
d ^= 1; ans++;
}
else {
for (int i=p-1; i>=1; --i) {
if (m >= a[i]) {
a[i] = INF;
m++; p = i;
flag = true;
}
}
if (m == n) break;
d ^= 1; ans++;
}
}
printf ("%d
", ans);
return 0;
}
题意：给了一张GCD表，问原来的求GCD的那些数
分析：从大到小找，最大的数和其他的数的GCD都不大于它，每次找到一个就能把它和已知的答案的GCD给删除，map+暴力就可以了
/************************************************
* Author :Running_Time
* Created Time :2015/10/3 星期六 21:53:35
* File Name :C.cpp
************************************************/
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int N = 5e2 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const double EPS = 1e-8;
int a[N*N];
int ans[N];
map<int, int> cnt;
int GCD(int a, int b) {
return b ? GCD (b, a % b) : a;
}
int main(void) {
int n; scanf ("%d", &n);
int m = n;
n = n * n;
for (int i=1; i<=n; ++i) {
scanf ("%d", &a[i]);
cnt[-a[i]]++;
}
int pos = m;
map<int, int>::iterator it;
for (it=cnt.begin (); it!=cnt.end (); ++it) {
int x = -it -> first;
while (it -> second) {
ans[pos] = x;
--it -> second;
for (int i=pos+1; i<=m; ++i) {
cnt[-GCD (ans[pos], ans[i])] -= 2;
}
pos--;
}
}
for (int i=1; i<=m; ++i) {
printf ("%d%c", ans[i], (i == m) ? '
' : ' ');
}
return 0;
}