TopCoder SRM 588: KeyDungeonDiv2
Count() を使うだけ
public class KeyDungeonDiv2 { public int countDoors(int[] doorR, int[] doorG, int[] keys) { return Enumerable.Range(0, doorR.Length) .Count(index => Math.Max(doorR[index] - keys[0], 0) + Math.Max(doorG[index] - keys[1], 0) <= keys[2] ); } }