OJ-Problems-Source/HDOJ/1966_autoAC.cpp

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#include <stdio.h>
#include <string.h>
#include <math.h>
#define min(a,b) ((a)<(b)?(a):(b))
#define max(a,b) ((a)>(b)?(a):(b))
#define INF 0x3f3f3f3f
const int N = 55;
const double eps = 1e-6;
int t, n;
double dp[N][N];
struct Point {
double x, y;
void read() {
scanf("%lf%lf", &x, &y);
}
} p[N];
double area(Point a, Point b, Point c) {
return fabs((b.x - a.x) * (c.y - a.y) - (c.x - a.x) * (b.y - a.y)) / 2.0;
}
void init() {
scanf("%d", &n);
for (int i = 0; i < n; i++)
p[i].read();
}
bool judge(int i, int j, int k) {
double s = area(p[i], p[j], p[k]);
for (int x = 0; x < n; x++) {
if (x == i || x == j || x == k) continue;
double sum = area(p[i], p[j], p[x]) + area(p[i], p[k], p[x]) + area(p[k], p[j], p[x]);
if (fabs(sum - s) < eps) return false;
}
return true;
}
double solve() {
double ans = INF;
for (int len = 2; len < n; len++) {
for (int l = 0; l < n; l++) {
int r = (l + len) % n;
dp[l][r] = INF;
for (int k = (l + 1) % n; k != r; k = (k + 1) % n) {
if (!judge(l, k, r)) continue;
dp[l][r] = min(dp[l][r], max(max(dp[l][k], dp[k][r]), area(p[l], p[k], p[r])));
}
if (len == n - 1)
ans = min(ans, dp[l][r]);
}
}
return ans;
}
int main() {
scanf("%d", &t);
while (t--) {
init();
printf("%.1lf\n", solve());
}
return 0;
}