update 53 java, progress

yennanliu · May 24, 2024 · 0922d83 · 0922d83
1 parent 2382e37
commit 0922d83
Show file tree

Hide file tree

Showing 4 changed files with 110 additions and 10 deletions.
diff --git a/data/progress.txt b/data/progress.txt
@@ -1,4 +1,4 @@
-20240524: 55
+20240524: 55,54(todo),53
 20240523: 56
 20240522: 62,572,57
 20240521: 322,191,190

diff --git a/data/to_review.txt b/data/to_review.txt
@@ -1,4 +1,4 @@
-2024-07-18 -> ['55']
+2024-07-18 -> ['55,54(todo),53']
 2024-07-17 -> ['56']
 2024-07-16 -> ['62,572,57']
 2024-07-15 -> ['322,191,190']
@@ -13,7 +13,7 @@
 2024-07-06 -> ['371']
 2024-07-05 -> ['121,252']
 2024-07-04 -> ['125']
-2024-06-27 -> ['55']
+2024-06-27 -> ['55,54(todo),53']
 2024-06-26 -> ['56']
 2024-06-25 -> ['62,572,57']
 2024-06-24 -> ['322,191,190']
@@ -26,27 +26,27 @@
 2024-06-17 -> ['105,106']
 2024-06-16 -> ['242,235']
 2024-06-15 -> ['371']
-2024-06-14 -> ['55', '121,252']
+2024-06-14 -> ['55,54(todo),53', '121,252']
 2024-06-13 -> ['56', '125']
 2024-06-12 -> ['62,572,57']
 2024-06-11 -> ['322,191,190']
 2024-06-10 -> ['73,200,70,323(again)']
 2024-06-09 -> ['207,79,206,213,198']
 2024-06-08 -> ['212(todo),211,338,208(again)']
 2024-06-07 -> ['347,253(todo),91(todo),217']
-2024-06-06 -> ['55', '226,98,253(todo)']
+2024-06-06 -> ['55,54(todo),53', '226,98,253(todo)']
 2024-06-05 -> ['56', '104,230,102,100']
 2024-06-04 -> ['62,572,57', '105,106']
 2024-06-03 -> ['322,191,190', '242,235']
 2024-06-02 -> ['73,200,70,323(again)', '371']
-2024-06-01 -> ['55', '207,79,206,213,198', '121,252']
+2024-06-01 -> ['55,54(todo),53', '207,79,206,213,198', '121,252']
 2024-05-31 -> ['56', '212(todo),211,338,208(again)', '125']
 2024-05-30 -> ['62,572,57', '347,253(todo),91(todo),217']
-2024-05-29 -> ['55', '322,191,190', '226,98,253(todo)']
+2024-05-29 -> ['55,54(todo),53', '322,191,190', '226,98,253(todo)']
 2024-05-28 -> ['56', '73,200,70,323(again)', '104,230,102,100']
-2024-05-27 -> ['55', '62,572,57', '207,79,206,213,198', '105,106']
-2024-05-26 -> ['55', '56', '322,191,190', '212(todo),211,338,208(again)', '242,235']
-2024-05-25 -> ['55', '56', '62,572,57', '73,200,70,323(again)', '347,253(todo),91(todo),217', '371']
+2024-05-27 -> ['55,54(todo),53', '62,572,57', '207,79,206,213,198', '105,106']
+2024-05-26 -> ['55,54(todo),53', '56', '322,191,190', '212(todo),211,338,208(again)', '242,235']
+2024-05-25 -> ['55,54(todo),53', '56', '62,572,57', '73,200,70,323(again)', '347,253(todo),91(todo),217', '371']
 2024-05-24 -> ['56', '62,572,57', '322,191,190', '207,79,206,213,198', '226,98,253(todo)', '121,252']
 2024-05-23 -> ['62,572,57', '322,191,190', '73,200,70,323(again)', '212(todo),211,338,208(again)', '104,230,102,100', '125']
 2024-05-22 -> ['322,191,190', '73,200,70,323(again)', '207,79,206,213,198', '347,253(todo),91(todo),217', '105,106']

diff --git a/leetcode_java/src/main/java/LeetCodeJava/Greedy/MaximumSubarray.java b/leetcode_java/src/main/java/LeetCodeJava/Greedy/MaximumSubarray.java
@@ -63,7 +63,18 @@ public int maxSubArray_(int[] nums) {
         int cumSum = 0;
 
         for (int i = 0; i < nums.length; i++){
+            /** NOTE !!!
+             *
+             *  ONLY use "cumSum + nums[i]" as condition
+             *  to check whether give up current cumsum, and create a new one
+             *  or keep cumsum
+             */
             if (cumSum + nums[i] < 0){
+                /**
+                 * NOTE !!!
+                 *    if cumSum + nums[i] < 0,
+                 *    still need to get max val from (ans, cumSum + nums[i])
+                 */
                 ans = Math.max(ans, cumSum + nums[i]);
                 cumSum = 0;
             }else{
@@ -75,6 +86,63 @@ public int maxSubArray_(int[] nums) {
         return ans;
     }
 
+    // V0''
+    // IDEA : BRUTE FORCE (by GPT)
+    public int maxSubArray_0(int[] nums) {
+        // If there is only one element, the maximum subarray is the element itself
+        if (nums.length == 1) {
+            return nums[0];
+        }
+
+        // Initialize variables
+        int res = nums[0]; // This will store the maximum subarray sum
+        int cur = nums[0]; // This will store the current subarray sum
+
+        // Iterate through the array starting from the second element
+        for (int i = 1; i < nums.length; i++) {
+            // Update current subarray sum
+            cur = Math.max(nums[i], cur + nums[i]);
+
+            // Update the result with the maximum value found so far
+            res = Math.max(res, cur);
+        }
+
+        return res;
+    }
+
+    // V0'''
+    // IDEA : GREEDY (modified by GPT)
+    public int maxSubArray_0_1(int[] nums) {
+
+        if (nums.length == 1) {
+            return nums[0];
+        }
+
+        int res = nums[0];
+        int cur = nums[0];
+
+        // Left pointer (l) and right pointer (r) initialized to the first element
+        //int l = 0;
+        int r = 1;
+
+        while (r < nums.length) {
+            // If current sum is negative, reset it to the current element
+            if (cur < 0) {
+                //l = r;
+                cur = nums[r];
+            } else {
+                // Otherwise, add the current element to the current sum
+                cur += nums[r];
+            }
+            // Update the result with the maximum value found so far
+            res = Math.max(res, cur);
+            r++;
+        }
+
+        return res;
+    }
+
+
     // V1
     // IDEA : OPTIMIZED BRUTE FORCE (TLE)
     // https://leetcode.com/problems/maximum-subarray/editorial/

diff --git a/leetcode_java/src/main/java/dev/workspace3.java b/leetcode_java/src/main/java/dev/workspace3.java
@@ -1522,4 +1522,36 @@ public boolean canJump(int[] nums) {
         return dist >= nums.length-1; // dist < nums.length ? false : true;
     }
 
+    // LC 53
+    // sliding window
+    public int maxSubArray(int[] nums) {
+
+        if (nums.length==1){
+            return nums[0];
+        }
+
+        int res = -1 * Integer.MAX_VALUE;
+        int cur = 0;
+        //List<Integer> cache = new ArrayList<>();
+        int l = 0;
+        int r = 0;
+
+        while (r < nums.length){
+            System.out.println("l = " + l + " r = " + r + " cur = " + cur + " res = " + res);
+            int updated = cur + nums[r];
+            if (r == 0 || updated > 0) {
+                cur += nums[r];
+                r += 1;
+                res = Math.max(res, cur);
+            } else {
+                r += 1;
+                l = r;
+                cur = 0;
+                res = Math.max(res, cur);
+            }
+        }
+
+        return res;
+    }
+
 }