POJ 2718Smallest Difference（DFS）

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不知道有啥简单方法，，，傻逼式暴力出来的。
#pragma warning(disable:4996)#include <cstdio>#include <cmath>#include <cstring>#include <algorithm>#include <iostream>#include <vector>using namespace std;int num[10], a[10], b[10], cnt1, cnt2;vector<int>x, y;bool vis[10];void dfs(int num[], int type, int pos, int cnt, int ret) {if (pos == 0) {if (type == 1)x.push_back(ret);else y.push_back(ret);return;}for (int i = 0; i < cnt; i++) {if (vis[i])continue;if (num[i] == 0 && pos == cnt&&cnt != 1)continue;int nxt = ret + num[i] * (int)pow(10.0, (pos - 1)*1.0);vis[i] = true;dfs(num, type, pos - 1, cnt, nxt);vis[i] = false;}}int getMax(int num[], int cnt) {int ret = 0;for (int i = cnt - 1; i >= 0; i--) {ret += num[i] * (int)pow(10.0, i*1.0);}return ret;}int getMin(int num[], int cnt) {int ret = 0;if (num[0] == 0) {if (cnt == 1)return 0;else {swap(num[0], num[1]);}}for (int i = 0; i < cnt; i++) {ret += num[i] * (int)pow(10.0, (cnt - 1 - i)*1.0);}return ret;}int main() {int t; scanf("%d", &t);while (t--) {int n = 0, X;while (cin >> X) {num[n++] = X;if (cin.peek() == '\n')break;}int ans = -1;for (int i = 1; i < (1 << n) - 1; i++) {cnt1 = cnt2 = 0;int tmp = i, id = 0;while (tmp) {if (tmp & 1)a[cnt1++] = num[id];else b[cnt2++] = num[id];id++;tmp >>= 1;}while (id < n)b[cnt2++] = num[id++];if (cnt1 == cnt2) {x.clear();y.clear();memset(vis, false, sizeof vis);dfs(a, 1, cnt1, cnt1, 0);memset(vis, false, sizeof vis);dfs(b, 2, cnt2, cnt2, 0);for (int u = 0; u < (int)x.size(); u++) {for (int v = 0; v < (int)y.size(); v++) {int tmp = abs(x[u] - y[v]);if (ans == -1)ans = tmp;else ans = min(tmp, ans);}}}else {if (cnt1 > cnt2) {int tmp = getMin(a, cnt1) - getMax(b, cnt2);if (tmp < 0)tmp = -tmp;if (ans == -1)ans = tmp;else ans = min(tmp, ans);}else {int tmp = getMin(b, cnt2) - getMax(a, cnt1);if (tmp < 0)tmp = -tmp;if (ans == -1)ans = tmp;else ans = min(tmp, ans);}}}printf("%d\n", ans);}return 0;}
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