題目鏈接:洛谷P2036
一看數據範圍,直接想到二進制枚舉子集
int main()
{
// fre;
int n;
cin >> n;
int ans = INF;
int a[12], b[12];
for (int i = 1; i <= n; i++)
cin >> a[i] >> b[i];
for (int i = 1; i < (1 << n); i++)
{
int s1 = 1;
int s2 = 0;
for (int j = 0; j < n; j++)
if ((1 << j) & i)
s1 *= a[j + 1], s2 += b[j + 1];
ans = (ans > fabs(s1 - s2)) ? fabs(s1 - s2) : ans;
}
cout << ans << endl;
return 0;
}
另外也可以DFS,不過我覺得思路和二進制枚舉子集差不多。
int n;
int a[12], b[12];
int ans = INF;
void dfs(int now, int s1, int s2, int ff)
{
if (now > n + 1)
return;
dfs(now + 1, s1 * a[now], s2 + b[now], 1);
dfs(now + 1, s1, s2, ff);
if (now == n + 1 && ff)
ans = min(ans, (int)fabs(s1 - s2));
}
int main()
{
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i] >> b[i];
dfs(1, 1, 0, 0);
cout << ans << endl;
return 0;
}