hdu 4334 Trouble
题目连接
http://acm.hdu.edu.cn/showproblem.php?pid=4334
Trouble
Description
Hassan is in trouble. His mathematics teacher has given him a very difficult problem called 5-sum. Please help him.
The 5-sum problem is defined as follows: Given 5 sets S_1,...,S_5 of n integer numbers each, is there a_1 in S_1,...,a_5 in S_5 such that a_1+...+a_5=0?
Input
First line of input contains a single integer N (1≤N≤50). N test-cases follow. First line of each test-case contains a single integer n (1<=n<=200). 5 lines follow each containing n integer numbers in range [-10^15, 1 0^15]. I-th line denotes set S_i for 1<=i<=5.
Output
For each test-case output "Yes" (without quotes) if there are a_1 in S_1,...,a_5 in S_5 such that a_1+...+a_5=0, otherwise output "No".
Sample Input
2
2
1 -1
1 -1
1 -1
1 -1
1 -1
3
1 2 3
-1 -2 -3
4 5 6
-1 3 2
-4 -10 -1
Sample Output
No
Yes
简单哈希。。
#include<algorithm> #include<iostream> #include<cstdlib> #include<cstring> #include<cstdio> #include<vector> #include<map> using std::abs; using std::min; using std::find; using std::pair; using std::vector; using std::multimap; #define pb(e) push_back(e) #define sz(c) (int)(c).size() #define mp(a, b) make_pair(a, b) #define all(c) (c).begin(), (c).end() #define iter(c) __typeof((c).begin()) #define cls(arr, val) memset(arr, val, sizeof(arr)) #define cpresent(c, e) (find(all(c), (e)) != (c).end()) #define rep(i, n) for(int i = 0; i < (int)n; i++) #define tr(c, i) for(iter(c) i = (c).begin(); i != (c).end(); ++i) const int N = 1000007; const int INF = 0x3f3f3f3f; typedef long long ll; struct Hash_Set { ll num[N << 1]; int tot, head[N], next[N]; inline void init() { tot = 0, cls(head, -1); } inline void insert(ll val) { ll u = abs(val) % N; num[tot] = val, next[tot] = head[u], head[u] = tot++; } inline bool find(ll val) { ll u = abs(val) % N; for(int i = head[u]; ~i; i = next[i]) { if(num[i] == val) return true; } return false; } }hash; ll A[5][210]; int main() { #ifdef LOCAL freopen("in.txt", "r", stdin); freopen("out.txt", "w+", stdout); #endif ll val; int t, n; scanf("%d", &t); while(t--) { hash.init(); scanf("%d", &n); rep(i, 5) { rep(j, n) scanf("%lld", &A[i][j]); } rep(i, n) { rep(j, n) { val = A[0][i] + A[1][j]; hash.insert(val); } } bool f = false; rep(i, n) { rep(j, n) { rep(k, n) { val = A[2][i] + A[3][j] + A[4][k]; val = -val; if(hash.find(val)) { f = true; break; } } if(f) break; } if(f) break; } puts(f ? "Yes" : "No"); } return 0; }