uploaded R solution for 1671

Author: choppystick

Diff for: Daily Problems/Hard/1671. Minimum Number of Removals to Make Mountain Array/solution.R

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+minimumMountainRemovals <- function(nums) {
+  n <- length(nums)
+
+  # Calculate LIS from the left side
+  left_lis <- integer(n)
+  temp <- c()
+  for (i in 1:n) {
+    pos <- findInterval(nums[i], temp, left.open = TRUE) + 1
+    if (pos > length(temp)) {
+      temp <- c(temp, nums[i])
+    } else {
+      temp[pos] <- nums[i]
+    }
+    left_lis[i] <- pos
+  }
+
+  # Calculate LIS from the right side (for LDS)
+  right_lis <- integer(n)
+  temp <- c()
+  for (i in n:1) {
+    pos <- findInterval(nums[i], temp, left.open = TRUE) + 1
+    if (pos > length(temp)) {
+      temp <- c(temp, nums[i])
+    } else {
+      temp[pos] <- nums[i]
+    }
+    right_lis[i] <- pos
+  }
+
+  # Calculate the maximum mountain length
+  max_mountain <- 0
+  for (i in 2:(n - 1)) {
+    if (left_lis[i] >= 2 && right_lis[i] >= 2) {
+      max_mountain <- max(max_mountain, left_lis[i] + right_lis[i] - 1)
+    }
+  }
+
+  # Return minimum elements to remove
+  if (max_mountain > 0) {
+    return(n - max_mountain)
+  } else {
+    return(n)
+  }
+}
+
+# Example usage
+nums1 <- c(1, 3, 1)
+nums2 <- c(2,1,1,5,6,2,3,1)
+nums3 <- c(100,92,89,77,74,66,64,66,64)
+print(minimumMountainRemovals(nums1))  # Output: 0
+print(minimumMountainRemovals(nums2))
+print(minimumMountainRemovals(nums3))