update: 添加问题“2906.构造乘积矩阵”的代码和题解 (#1462)

* archive: modifies yesterday

* clean: rename

Signed-off-by: LetMeFly666 <Tisfy@qq.com>

* word: en 2025.3.24

* 1886: AC,i=3break,100.00%,6.20% (#1458)(#1457)

* 2906: CE.cpp (#1461)

Line 18: Char 14: error: inline declaration of 'getIndex' not allowed in block scope
   18 |         auto inline getIndex = [&](const int& t) {
      |              ^~~~~~
1 error generated.

* 2906: RE.cpp (#1461) - index err

* 2906: AC.cpp (#1461) - AC,13.89%,8.33%

* 2906: AC.cpp.O1 (#1461) - AC,61.11%,91.67%

* update: 添加问题“2906.构造乘积矩阵”的代码和题解 (#1462)

Signed-off-by: LetMeFly666 <Tisfy@qq.com>

---------

Signed-off-by: LetMeFly666 <Tisfy@qq.com>

Author: LetMeFly666

.commitmsg

@@ -2,13 +2,12 @@
  * @Author: LetMeFly
  * @Date: 2026-03-23 21:32:36
  * @LastEditors: LetMeFly.xyz
- * @LastEditTime: 2026-03-23 21:45:04
+ * @LastEditTime: 2026-03-23 22:00:02
  */
 #ifdef _DEBUG
 #include "_[1,2]toVector.h"
 #endif
 
-// THIS CANNOT BE ACCEPTED
 typedef long long ll;
 const ll MOD = 1e9 + 7;
 class Solution {
@@ -17,21 +16,54 @@ class Solution {
         int n = grid.size(), m = grid[0].size();
         vector<vector<ll>> maximum(n, vector<ll>(m));
         vector<vector<ll>> minimum(n, vector<ll>(m));
-        for (int i = 0; i < n; i++) {
-            for (int j = 0; j < m; j++) {
-                ll left_max = j ? maximum[i][j - 1] : 1;
-                ll left_min = j ? minimum[i][j - 1] : 1;
-                ll up_max = i ? maximum[i - 1][j] : 1;
-                ll up_min = i ? minimum[i - 1][j] : 1;
+
+        maximum[0][0] = minimum[0][0] = grid[0][0];
+        for (int i = 1; i < n; i++) {
+            maximum[i][0] = minimum[i][0] = maximum[i - 1][0] * grid[i][0];
+        }
+        for (int j = 1; j < m; j++) {
+            maximum[0][j] = minimum[0][j] = maximum[0][j - 1] * grid[0][j];
+        }
+
+        for (int i = 1; i < n; i++) {
+            for (int j = 1; j < m; j++) {
                 if (grid[i][j] >= 0) {
-                    maximum[i][j] = max(left_max, up_max) * grid[i][j] % MOD;
-                    minimum[i][j] = max(left_min, up_min) * grid[i][j] % MOD;
+                    maximum[i][j] = max(maximum[i][j - 1], maximum[i - 1][j]) * grid[i][j];
+                    minimum[i][j] = min(minimum[i][j - 1], minimum[i - 1][j]) * grid[i][j];
                 } else {
-                    maximum[i][j] = max(left_min, up_min) * grid[i][j] % MOD;
-                    minimum[i][j] = max(left_max, up_max) * grid[i][j] % MOD;
+                    maximum[i][j] = min(minimum[i][j - 1], minimum[i - 1][j]) * grid[i][j];
+                    minimum[i][j] = max(maximum[i][j - 1], maximum[i - 1][j]) * grid[i][j];
                 }
             }
         }
-        return maximum[n - 1][m - 1] >= 0 ? maximum[n - 1][m - 1] : -1;
+
+        return maximum[n - 1][m - 1] >= 0 ? maximum[n - 1][m - 1] % MOD : -1;
+    }
+};
+
+#ifdef _DEBUG
+/*
+[[-1,-2,-3],[-2,-3,-3],[-3,-3,-2]]
+
+之前的逻辑：
+ll left_max = j ? maximum[i][j - 1] : 1;
+ll left_min = j ? minimum[i][j - 1] : 1;
+ll up_max = i ? maximum[i - 1][j] : 1;
+ll up_min = i ? minimum[i - 1][j] : 1;
+minimum[i][j] = max(left_max, up_max) * grid[i][j];  // when grid[i][j] < 0
+错在：
+-1 -2
+在-2时候，min和max都应该是2，但是max(-1, 1)会导致计算结果为-2。
+
+-1
+*/
+int main() {
+    string s;
+    while (cin >> s) {
+        Solution sol;
+        vector<vector<int>> v = stringToVectorVector(s);
+        cout << sol.maxProductPath(v) << endl;
     }
-};
+    return 0;
+}
+#endif

Codes/1594-maximum-non-negative-product-in-a-matrix.cpp

@@ -2,7 +2,7 @@
  * @Author: LetMeFly
  * @Date: 2026-03-22 23:35:27
  * @LastEditors: LetMeFly.xyz
- * @LastEditTime: 2026-03-22 23:45:34
+ * @LastEditTime: 2026-03-24 21:44:44
  */
 #ifdef _DEBUG
 #include "_[1,2]toVector.h"
@@ -16,7 +16,7 @@ class Solution {
             if (mat == target) {
                 return true;
             }
-            if (t == 4) {
+            if (t == 3) {
                 break;
             }
             vector<vector<int>> tmp(n, vector<int>(n));

Codes/1594-maximum-non-negative-product-in-a-matrix_AC.cpp

@@ -0,0 +1,44 @@
+/*
+ * @Author: LetMeFly
+ * @Date: 2026-03-24 21:47:35
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2026-03-24 22:02:21
+ */
+#ifdef _DEBUG
+#include "_[1,2]toVector.h"
+#endif
+
+typedef long long ll;
+const ll MOD = 12345;
+class Solution {
+public:
+    vector<vector<int>> constructProductMatrix(vector<vector<int>>& grid) {
+        int n = grid.size(), m = grid[0].size();
+
+        auto getIndex = [&](const int& t) {
+            return pair<int, int>{t / m, t % m};
+        };
+
+        vector<vector<ll>> prefix(n, vector<ll>(m, 1));
+        for (int t = 1; t < m * n; t++) {
+            auto [i1, j1] = getIndex(t);
+            auto [i0, j0] = getIndex(t - 1);
+            prefix[i1][j1] = prefix[i0][j0] * grid[i0][j0] % MOD;
+        }
+
+        vector<vector<ll>> suffix(n, vector<ll>(m, 1));
+        for (int t = m * n - 2; t >= 0; t--) {
+            auto [i0, j0] = getIndex(t);
+            auto [i1, j1] = getIndex(t + 1);
+            suffix[i0][j0] = suffix[i1][j1] * grid[i1][j1] % MOD;
+        }
+
+        vector<vector<int>> ans(n, vector<int>(m, 1));
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                ans[i][j] = prefix[i][j] * suffix[i][j] % MOD;
+            }
+        }
+        return ans;
+    }
+};

…atrix-can-be-obtained-by-rotation_AC.cpp …r-matrix-can-be-obtained-by-rotation.cppCodes/1886-determine-whether-matrix-can-be-obtained-by-rotation_AC.cpp renamed to Codes/1886-determine-whether-matrix-can-be-obtained-by-rotation.cpp Codes/1886-determine-whether-matrix-can-be-obtained-by-rotation_AC.cpp renamed to Codes/1886-determine-whether-matrix-can-be-obtained-by-rotation.cpp

@@ -0,0 +1,38 @@
+/*
+ * @Author: LetMeFly
+ * @Date: 2026-03-24 22:02:44
+ * @LastEditors: LetMeFly.xyz
+ * @LastEditTime: 2026-03-24 22:07:50
+ */
+#ifdef _DEBUG
+#include "_[1,2]toVector.h"
+#endif
+
+typedef long long ll;
+const ll MOD = 12345;
+class Solution {
+public:
+    vector<vector<int>> constructProductMatrix(vector<vector<int>>& grid) {
+        int n = grid.size(), m = grid[0].size();
+
+        auto getIndex = [&](const int& t) {
+            return pair<int, int>{t / m, t % m};
+        };
+
+        vector<vector<int>> ans(n, vector<int>(m, 1));
+        for (int t = 1; t < m * n; t++) {
+            auto [i1, j1] = getIndex(t);
+            auto [i0, j0] = getIndex(t - 1);
+            ans[i1][j1] = (ll)ans[i0][j0] * grid[i0][j0] % MOD;
+        }
+
+        ll suffix = 1;
+        for (int t = m * n - 2; t >= 0; t--) {
+            auto [i0, j0] = getIndex(t);
+            auto [i1, j1] = getIndex(t + 1);
+            suffix = suffix * grid[i1][j1] % MOD;
+            ans[i0][j0] = ans[i0][j0] * suffix % MOD;
+        }
+        return ans;
+    }
+};

Codes/1886-determine-whether-matrix-can-be-obtained-by-rotation.cpp.cpp

@@ -971,6 +971,7 @@
 |2894.分类求和并作差|简单|<a href="https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2025/05/27/LeetCode%202894.%E5%88%86%E7%B1%BB%E6%B1%82%E5%92%8C%E5%B9%B6%E4%BD%9C%E5%B7%AE/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/148266123" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/divisible-and-non-divisible-sums-difference/solutions/3687620/letmefly-2894fen-lei-qiu-he-bing-zuo-cha-suyc/" target="_blank">LeetCode题解</a>|
 |2900.最长相邻不相等子序列I|简单|<a href="https://leetcode.cn/problems/longest-unequal-adjacent-groups-subsequence-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2025/05/15/LeetCode%202900.%E6%9C%80%E9%95%BF%E7%9B%B8%E9%82%BB%E4%B8%8D%E7%9B%B8%E7%AD%89%E5%AD%90%E5%BA%8F%E5%88%97I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/147990003" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/longest-unequal-adjacent-groups-subsequence-i/solutions/3677963/letmefly-2900zui-chang-xiang-lin-bu-xian-69ua/" target="_blank">LeetCode题解</a>|
 |2903.找出满足差值条件的下标I|简单|<a href="https://leetcode.cn/problems/find-indices-with-index-and-value-difference-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/05/25/LeetCode%202903.%E6%89%BE%E5%87%BA%E6%BB%A1%E8%B6%B3%E5%B7%AE%E5%80%BC%E6%9D%A1%E4%BB%B6%E7%9A%84%E4%B8%8B%E6%A0%87I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/139195914" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/find-indices-with-index-and-value-difference-i/solutions/2789520/letmefly-2903zhao-chu-man-zu-chai-zhi-ti-m92q/" target="_blank">LeetCode题解</a>|
+|2906.构造乘积矩阵|中等|<a href="https://leetcode.cn/problems/construct-product-matrix/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2026/03/24/LeetCode%202906.%E6%9E%84%E9%80%A0%E4%B9%98%E7%A7%AF%E7%9F%A9%E9%98%B5/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/159436536" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/construct-product-matrix/solutions/3935999/letmefly-2906gou-zao-cheng-ji-ju-zhen-qi-g1ev/" target="_blank">LeetCode题解</a>|
 |2908.元素和最小的山形三元组I|简单|<a href="https://leetcode.cn/problems/minimum-sum-of-mountain-triplets-i/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/03/29/LeetCode%202908.%E5%85%83%E7%B4%A0%E5%92%8C%E6%9C%80%E5%B0%8F%E7%9A%84%E5%B1%B1%E5%BD%A2%E4%B8%89%E5%85%83%E7%BB%84I/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/137151595" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/minimum-sum-of-mountain-triplets-i/solutions/2714346/letmefly-2908yuan-su-he-zui-xiao-de-shan-h3s9/" target="_blank">LeetCode题解</a>|
 |2917.找出数组中的K-or值|简单|<a href="https://leetcode.cn/problems/find-the-k-or-of-an-array/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2024/03/06/LeetCode%202917.%E6%89%BE%E5%87%BA%E6%95%B0%E7%BB%84%E4%B8%AD%E7%9A%84K-or%E5%80%BC/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/136497896" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/find-the-k-or-of-an-array/solutions/2670279/letmefly-2917zhao-chu-shu-zu-zhong-de-k-4wuuh/" target="_blank">LeetCode题解</a>|
 |2918.数组的最小相等和|中等|<a href="https://leetcode.cn/problems/minimum-equal-sum-of-two-arrays-after-replacing-zeros/" target="_blank">题目地址</a>|<a href="https://blog.letmefly.xyz/2025/05/10/LeetCode%202918.%E6%95%B0%E7%BB%84%E7%9A%84%E6%9C%80%E5%B0%8F%E7%9B%B8%E7%AD%89%E5%92%8C/" target="_blank">题解地址</a>|<a href="https://letmefly.blog.csdn.net/article/details/147858203" target="_blank">CSDN题解</a>|<a href="https://leetcode.cn/problems/minimum-equal-sum-of-two-arrays-after-replacing-zeros/solutions/3673509/letmefly-2918shu-zu-de-zui-xiao-xiang-de-b7ha/" target="_blank">LeetCode题解</a>|

Codes/2906-construct-product-matrix.cpp

@@ -80,7 +80,7 @@ public:
             if (mat == target) {
                 return true;
             }
-            if (t == 4) {
+            if (t == 3) {
                 break;
             }
             vector<vector<int>> tmp(n, vector<int>(n));