java: add «1937. Maximum Number of Points with Cost»

Signed-off-by: Matej Focko <me@mfocko.xyz>

java/maximum-number-of-points-with-cost.java

@@ -0,0 +1,30 @@
+class Solution {
+  public long maxPoints(int[][] points) {
+    int width = points[0].length;
+
+    var previous = new long[width];
+    for (var row : points) {
+      var current = new long[width];
+
+      long runningMaximum = 0;
+      for (int x = 0; x < width; ++x) {
+        runningMaximum = Math.max(runningMaximum - 1, previous[x]);
+        current[x] = runningMaximum;
+      }
+
+      runningMaximum = 0;
+      for (int x = width - 1; x >= 0; --x) {
+        runningMaximum = Math.max(runningMaximum - 1, previous[x]);
+        current[x] = Math.max(current[x], runningMaximum) + row[x];
+      }
+
+      previous = current;
+    }
+
+    var answer = previous[0];
+    for (var candidate : previous) {
+      answer = Math.max(answer, candidate);
+    }
+    return answer;
+  }
+}