ssdj

Author: thecodingwizard

Infoarena/ssdj.cpp

@@ -0,0 +1,68 @@
+/*
+ * Loop through all the characters; we'll find the number of submatrices that has
+ * one of the corners as the current character c.
+ *
+ * For a given character c, define above[i][j] = the first row r above row i such that
+ * A[r][j] >= c.
+ */
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+using ll = long long;
+#define ii pair<int, int>
+#define f first
+#define s second
+#define pb push_back
+#define mp make_pair
+#define all(x) x.begin(), x.end()
+#define sz(x) (int)x.size()
+#define F0R(i, n) for (int i = 0; i < n; i++)
+#define FOR(i, a, b) for (int i = a; i < b; i++)
+#define inf 1000000010
+
+int main() {
+    cin.tie(0)->sync_with_stdio(0);
+    freopen("ssdj.in", "r", stdin);
+    freopen("ssdj.out", "w", stdout);
+
+    int n; cin >> n;
+    char A[n][n];
+    F0R(i, n) F0R(j, n) cin >> A[i][j];
+
+    int above[n][n]; // index of row above (i, j) that's >= c
+    int ans = 0;
+    for (char c = 'z'; c >= 'a'; c--) {
+        F0R(col, n) {
+            int prev = -1;
+            F0R(row, n) {
+                above[row][col] = prev;
+                if (A[row][col] >= c) {
+                    prev = row;
+                }
+            }
+        }
+        F0R(row, n) {
+            int rightCol = -1;
+            int upperBound = -2;
+            for (int col = n-1; ~col; col--) {
+                if (A[row][col] >= c) {
+                    rightCol = col;
+                    upperBound = above[row][col]+1;
+                } else {
+                    if (rightCol == -1) continue;
+                    if (upperBound <= above[row][col]) {
+                        if (A[row][rightCol] == c || A[above[row][col]][col] == c) {
+                            ans++;
+                        }
+                        upperBound = above[row][col]+1;
+                    }
+                }
+            }
+        }
+    }
+    cout << ans << endl;
+
+    return 0;
+}

input.txt

@@ -0,0 +1,12 @@
+4
+1 3
+FFT 3
+1 3
+FFT 2
+2 6
+FFTTTF 2
+FTFTFT 4
+2 2
+FF 1
+TT 1
+