Compute the maximum water trapped by a pair of vertical lines - EPI

Compute the maximum water trapped by a pair of vertical lines 

ContainerWithMostWater.java

  public static int getMaxArea(List<Integer> heights) {

    int i = 0, j = heights.size() - 1;

    int res = 0;

    while (i < j) {

      res = Math.max(res, Math.min(heights.get(i), heights.get(j)) * (j - i));

      if (heights.get(i) > heights.get(j)) {

        --j;

      } else if (heights.get(i) < heights.get(j)) {

        ++i;

      } else { // heights[i] == heights[j].

        ++i;

        --j;

      }

    }

    return res;

  }