Coding Interview 8.2

1. a m * n matrix a [] []. The robot moves from the upper left corner to the lower right corner and can only go right or down to output all paths.

2. If some grids in the matrix can go, some grids cannot go, And all paths are output. (A [I] [j] = 1 indicates that you can go. a [I] [j] = 0 indicates that you cannot go)

Ideas:

Typical recursive algorithms. Question 1 directly uses the idea of deep search. Question 2 adds a judgment condition on the basis of Question 1.

 

# Include <iostream> # include <vector> using namespace std; struct Point {int x; int y; Point (int I, int j): x (I ), y (j) {}}; // Question 1 void Path1 (int x, int y, int m, int n, vector <Point> & vec, int len) {if (x = m | y = n) return; Point p (x, y); vec [len ++] = p; if (x = m-1 & y = n-1) {for (int I = 0; I <vec. size (); ++ I) cout <vec [I]. x <''<vec [I]. y <endl;} else {Path1 (x, y + 1, m, n, vec, len); Path1 (x + 1, y, m, n, vec, len) ;}} // Question 2 void Path2 (int x, int y, int m, int n, vector <Point> & vec, int len, int safe [] [4]) {if (x = m | y = n | safe [x] [y] = 0) return; point p (x, y); vec [len ++] = p; if (x = m-1 & y = n-1) {for (int I = 0; I <vec. size (); ++ I) cout <vec [I]. x <''<vec [I]. y <endl;} else {Path2 (x, y + 1, m, n, vec, len, safe); Path2 (x + 1, y, m, n, vec, len, safe) ;}} void main () {int m = 3, n = 4; int x = 0, y = 0; int len = 0; point p (0, 0); vector <Point> vec (m + n-1, p); Path1 (x, y, m, n, vec, len ); int safe [] [4] = {1, 1, 1, 0}, {0, 1, 1, 1}, {0, 0, 1, 1 }}; path2 (x, y, m, n, vec, len, safe );}