Sicily 1781. Knight

1781. Knight Constraints

Time limit:1 secs, Memory limit:64 MB

Description

Your task is to write a program to calculate the minimum number of moves needed for a knight to reach one point from anoth Er. The possible knight moves is shown in Figure 1.

Figure 1 Possible Knight moves on the board

Input

The first line contains an integer T (≤10), indicating the number of test cases.

In every case, the first line contains an integerN(≤500), indicating the size of the chess board (the entire board has a sizeN xN). The second and third line contain pair of integers (SRCR, SrcC), and (Dstr, DSTC), specifying the starting and ending Posi tion of the Knight on the Board (0≤SRCR, SrcC, Dstr, dstc≤N–1).

Output

For every case, the output of the minimum distance on a. If starting point and ending point was equal, distance is 0. If the knight can ' t reach the ending point, distance is-1.

Sample Input

21st

0 00 0100) 18 9

Sample Output

06

Knight Parade problem, bfs:0.01s

#include <stdio.h> #include <queue> #include <string.h>using namespace Std;int n;bool vis[505][505];    struct point {int II; int JJ;};        Point SP, Ep;int BFs () {if (Sp.ii = = Ep.ii && SP.JJ = = EP.JJ) return 0;    Queue<point> Q;    Memset (Vis, false, sizeof (VIS));    Q.push (SP);    Point temp, Temp_next;        int step = 0;        while (!q.empty ()) {step++;        int size = Q.size ();            while (size--) {temp = Q.front ();                        Q.pop (); if (Temp.ii > 1 && temp.jj < n-1 &&!VIS[TEMP.II-2][TEMP.JJ + 1]) {TEMP_NEXT.II                = Temp.ii-2;                TEMP_NEXT.JJ = temp.jj + 1;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next); } if (Temp.ii > 0 &&TEMP.JJ < n-2 &&!VIS[TEMP.II-1][TEMP.JJ + 2]) {TEMP_NEXT.II = temp.ii-1;                TEMP_NEXT.JJ = Temp.jj + 2;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                 } if (Temp.ii < n-1 && Temp.jj < n-2 &&!vis[temp.ii + 1][TEMP.JJ + 2]) {                TEMP_NEXT.II = Temp.ii + 1;                TEMP_NEXT.JJ = Temp.jj + 2;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                 } if (Temp.ii < n-2 && Temp.jj < n-1 &&!VIS[TEMP.II + 2][TEMP.JJ + 1]) {                TEMP_NEXT.II = Temp.ii + 2; Temp_nexT.JJ = temp.jj + 1;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                } if (Temp.ii < n-2 && temp.jj > 0 &&!VIS[TEMP.II + 2][temp.jj-1]) {                TEMP_NEXT.II = Temp.ii + 2;                TEMP_NEXT.JJ = temp.jj-1;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                } if (Temp.ii < n-1 && temp.jj > 1 &&!vis[temp.ii + 1][temp.jj-2]) {                TEMP_NEXT.II = Temp.ii + 1;                TEMP_NEXT.JJ = temp.jj-2;          if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;      } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                } if (Temp.ii > 0 && temp.jj > n-1 &&!vis[temp.ii-1][temp.jj-2]) {                TEMP_NEXT.II = temp.ii-1;                TEMP_NEXT.JJ = temp.jj-2;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);                } if (Temp.ii > 1 && temp.jj > 0 &&!vis[temp.ii-2][temp.jj-1]) {                TEMP_NEXT.II = temp.ii-2;                TEMP_NEXT.JJ = temp.jj-1;                if (Temp_next.ii = = Ep.ii && TEMP_NEXT.JJ = = ep.jj) {return step;                } VIS[TEMP_NEXT.II][TEMP_NEXT.JJ] = true;            Q.push (Temp_next);    }}} return-1;}        int main () {int case_num;    scanf ("%d", &case_num);        while (case_num--) {scanf ("%d", &n);        scanf ("%d%d%d%d", &sp.ii, &AMP;SP.JJ, &AMP;EP.II, &AMP;EP.JJ);    printf ("%d\n", BFS ());                  } return 0;}

Sicily 1781. Knight