Leetcode#64 Minimum Path Sum

原题地址

基本动态规划题

代码：

int minPathSum(vector<vector<int> > &grid) {
  if (grid.empty() || grid[0].empty()) return 0;

  int m = grid.size();
  int n = grid[0].size();
  vector<int> sum(n, 0);

  sum[n - 1] = grid[m - 1][n - 1];
  for (int j = n - 2; j >= 0; j--)
    sum[j] = grid[m - 1][j] + sum[j + 1];

  for (int i = m - 2; i >= 0; i--) {
    sum[n - 1] += grid[i][n - 1];
    for (int j = n - 2; j >= 0; j--)
      sum[j] = min(sum[j], sum[j + 1]) + grid[i][j];
  }

  return sum[0];
}