49 lines
1.1 KiB
C++
49 lines
1.1 KiB
C++
#include <stdio.h>
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#include <math.h>
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#define INF 0x7fffffff
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#define N 201
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struct point{
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double x, y;
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}point[N];
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int n;
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double dis[N][N];
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double distant(int i, int j)
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{
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return sqrt((point[i].x - point[j].x)*(point[i].x - point[j].x) + (point[i].y - point[j].y)*(point[i].y - point[j].y));
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}
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double dp()
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{
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int i, j, k;
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double temp, b[N][N];
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b[1][2] = dis[1][2];
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for (j=3; j<=n; j++)
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{
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for (i=1; i<=j-2; i++)
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b[i][j] = b[i][j-1] + dis[j-1][j];
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b[j-1][j] = INF;
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for (k=1; k<=j-2; k++)
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{
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temp = b[k][j-1] + dis[k][j];
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if (temp < b[j-1][j])
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b[j-1][j] = temp;
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}
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}
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b[n][n] = b[n-1][n] + dis[n-1][n];
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return b[n][n];
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}
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int main()
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{
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int i, j;
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double ans;
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while (scanf("%d", &n) > 0)
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{
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for (i=1; i<=n; i++)
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scanf("%lf %lf", &point[i].x, &point[i].y);
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for (j=2; j<=n; j++)
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for (i=1; i<j; i++)
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dis[i][j] = distant(i,j);
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ans = dp();
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printf("%.2lf\n", dp());
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}
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}
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