Topcoder SRM 345 DIV1 250

Test instructions: At first (0,0), to go to (x, y), each time only horizontal or vertical movement. Transverse movement, if the line y is even, then only the positive direction of the x-axis movement, if it is odd, can only move in the opposite direction of the x-axis, when the vertical movement, if the line x is even, then only the y-axis positive direction, if it is odd, can only move to the y-axis in the opposite direction. Q. What is the shortest distance from the starting point to the end point?

X, y range is [ -1e6, 1e6]

Solution: At first think of BFS (think very naturally), will (0, 0), (x, y), (x, 0), (0, Y) These 4 points respectively around 9 points (including themselves) as the point of accessibility. The BFS handles the shortest distance (0, 0) to (x, y). It was later found that there was a direct method of enumeration (x, y) in which quadrant, the parity of X, y to get the answer.

The second method of code

#include <cstdio>#include <iostream>#include <cstring>#include <cmath>using namespace STD;classpathfinding{ Public:intGetdirections (intXintY) {intAns =0;if(x >=0&& y >=0)        {if((x&1)==0|| (y&1)==0) ans =ABS(x) +ABS(y);ElseAns =ABS(x) +ABS(y) +2; }Else if(x <=0&& y <=0)        {if((x&1)==1|| (y&1)==1) ans =ABS(x) +ABS(y) +2;ElseAns =ABS(x) +ABS(y) +4; }Else if(X >0&& y <0)        {if((x&1)==1|| (y&1)==0) ans =ABS(x) +ABS(y);ElseAns =ABS(x) +ABS(y) +2; }Else if(X <0&& y >0)        {if((x&1)==0|| (y&1)==1) ans =ABS(x) +ABS(y);ElseAns =ABS(x) +ABS(y) +2; }returnAns }};

The first method of code

#include <cstring>#include <iostream>#include <queue>#include <algorithm>using namespace STD;structdata{intx, y;intIdintD;} d[100010];intnd queue<Data>QintTintminidis[100010];voidPushit (intX1,intY1) { for(inti =-1; I <=1; i++) { for(intj =-1; J <=1;            J + +) {++nd;            d[nd].x = x1 + I, D[nd].y = y1 + j; D[ND].D =1e9; }    }}BOOLCanget (data d1, data D2) {if(d1.x = = d2.x) {if((D1.x &1) && d1.y >= d2.y)return true;if((D1.x &1) ==0&& d1.y <= d2.y)return true; }if(d1.y = = d2.y) {if((D1.y &1) && d1.x >= d2.x)return true;if((D1.y &1) ==0&& d1.x <= d2.x)return true; }return false;}classpathfinding{ Public:intGetdirections (intXintY) {nd =0;        Pushit (x, y); Pushit (0,0); Pushit (x,0); Pushit (0, y);        Data Nowd; Nowd.x =0, Nowd.y =0, Nowd.d =0; Q.push (NOWD); while(!q.empty ())            {nowd = Q.front (); Q.pop (); for(inti =1; I <= nd; i++) {if(Canget (Nowd, D[i])) {if(Nowd.d +ABS(nowd.x-d[i].x) +ABS(NOWD.Y-D[I].Y) < D[I].D) {D[I].D = Nowd.d +ABS(nowd.x-d[i].x) +ABS(NOWD.Y-D[I].Y);                    Q.push (D[i]); }                }            }        }intAns =1e9; for(inti =1; I <= nd; i++) {if(d[i].x = = x && d[i].y = = y)            {ans = min (ans, d[i].d); }        }returnAns }};

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Topcoder SRM 345 DIV1 250