73 lines
1.3 KiB
C++
73 lines
1.3 KiB
C++
#include <cstdio>
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#include <cstring>
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#include <cmath>
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using namespace std;
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const double dd = sqrt(2.0)/2*10;
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int ti;
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double x,y;
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double d;
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double dis(double x1, double y1, double x2, double y2)
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{
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return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
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}
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void dfs(double x1,double y1,int dir,int tt)
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{
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double aa;
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dir %= 8;
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aa=dis(x1,y1,x,y);
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if(aa < d)
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{
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d = aa;
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}
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if(tt==ti ||(aa-10*(ti-tt)>d))
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{
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return ;
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}
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if(dir == 0)
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{
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dfs(x1+10,y1,dir,tt+1);
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}
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else if(dir == 1)
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{
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dfs(x1+dd,y1-dd,dir,tt+1);
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}
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else if(dir == 2)
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{
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dfs(x1,y1-10,dir,tt+1);
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}
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else if(dir == 3)
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{
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dfs(x1-dd,y1-dd,dir,tt+1);
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}
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else if(dir == 4)
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{
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dfs(x1-10,y1,dir,tt+1);
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}
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else if(dir == 5)
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{
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dfs(x1-dd,y1+dd,dir,tt+1);
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}
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else if(dir == 6)
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{
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dfs(x1,y1+10,dir,tt+1);
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}
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else if(dir == 7)
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{
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dfs(x1+dd,y1+dd,dir,tt+1);
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}
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dfs(x1,y1,dir+1,tt+1);
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}
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int main()
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{
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int t;
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scanf("%d",&t);
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while(t--)
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{
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scanf("%d%lf%lf",&ti,&x,&y);
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d = dis(0,0,x,y);
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dfs(0,0,0,0);
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printf("%.6lf\n",d);
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}
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return 0;
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}
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