题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5883
1 #include <bits/stdc++.h> 2 using namespace std; 3 #define fr first 4 #define sc second 5 #define cl clear 6 #define BUG puts("here!!!") 7 #define W(a) while(a--) 8 #define pb(a) push_back(a) 9 #define Rint(a) scanf("%d", &a) 10 #define Rll(a) scanf("%I64d", &a) 11 #define Rs(a) scanf("%s", a) 12 #define Cin(a) cin >> a 13 #define FRead() freopen("in", "r", stdin) 14 #define FWrite() freopen("out", "w", stdout) 15 #define Rep(i, len) for(int i = 0; i < (len); i++) 16 #define For(i, a, len) for(int i = (a); i < (len); i++) 17 #define Cls(a) memset((a), 0, sizeof(a)) 18 #define Clr(a, x) memset((a), (x), sizeof(a)) 19 #define Full(a) memset((a), 0x7f7f7f, sizeof(a)) 20 #define lrt rt << 1 21 #define rrt rt << 1 | 1 22 #define pi 3.14159265359 23 #define RT return 24 #define lowbit(x) x & (-x) 25 #define onecnt(x) __builtin_popcount(x) 26 typedef long long LL; 27 typedef long double LD; 28 typedef unsigned long long ULL; 29 typedef pair<int, int> pii; 30 typedef pair<string, int> psi; 31 typedef pair<LL, LL> pll; 32 typedef map<string, int> msi; 33 typedef vector<int> vi; 34 typedef vector<LL> vl; 35 typedef vector<vl> vvl; 36 typedef vector<bool> vb; 37 38 const int maxn = 100100; 39 int n, m; 40 int ret, tmp; 41 int a[maxn], in[maxn]; 42 int pre[maxn]; 43 44 int find(int x) { 45 return x == pre[x] ? x : pre[x] = find(pre[x]); 46 } 47 48 void unite(int x, int y) { 49 x = find(x); 50 y = find(y); 51 if(x != y) pre[x] = y; 52 } 53 54 signed main() { 55 // FRead(); 56 int T, u, v; 57 Rint(T); 58 W(T) { 59 Cls(in); ret = 0; 60 Rint(n); Rint(m); 61 For(i, 1, n+1) { 62 pre[i] = i; 63 Rint(a[i]); 64 } 65 Rep(i, m) { 66 Rint(u); Rint(v); 67 in[u]++; in[v]++; 68 unite(u, v); 69 } 70 int flag = 0; 71 For(i, 1, n+1) if(in[i] & 1) flag++; 72 if(flag > 2 || flag == 1) { 73 puts("Impossible"); 74 continue; 75 } 76 For(i, 1, n+1) { 77 tmp = (in[i] + 1) / 2; 78 W(tmp) ret ^= a[i]; 79 } 80 if(flag == 2) { 81 printf("%d ", ret); 82 continue; 83 } 84 tmp = 0; 85 For(i, 1, n+1) { 86 if(in[i] != 0) { 87 int cur = ret ^ a[i]; 88 tmp = max(tmp, cur); 89 } 90 } 91 printf("%d ", tmp); 92 } 93 RT 0; 94 }