Create split-array-into-fibonacci-sequence.cpp

Author: kamyu104

C++/split-array-into-fibonacci-sequence.cpp

@@ -0,0 +1,52 @@
+// Time:  O(n^3)
+// Space: O(n)
+
+class Solution {
+public:
+    vector<int> splitIntoFibonacci(string S) {
+        for (int i = 0, a = 0; i + 2 < S.length(); ++i) {
+            a = 10 * a + S[i] - '0';
+            for (int j = i + 1, b = 0; j + 1 < S.length(); ++j) {
+                b = 10 * b + S[j] - '0';
+                vector<int> fib = {a, b};
+                int k = j + 1;
+                while (k < S.length()) {
+                    if (fib[fib.size() - 2] > numeric_limits<int>::max() - fib[fib.size() - 1]) {
+                        break;
+                    }
+                    auto c = fib[fib.size() - 2] + fib[fib.size() - 1];
+                    auto l = startswith(S, k, c);
+                    if (l == 0) {
+                        break;
+                    }
+                    fib.emplace_back(c);
+                    k += l;
+                }
+                if (k == S.length()) {
+                    return fib;
+                }
+                if (b == 0) {
+                    break;
+                }
+            }
+            if (a == 0) {
+                break;
+            }
+        }
+        return {};
+    }
+
+private:
+    int startswith(const string& S, int k, int x) {
+        int y = 0;
+        for (int i = k; i < S.length(); ++i) {
+            y = 10 * y + S[i] - '0';
+            if (y == x) {
+                return i - k + 1;
+            } else if (y > x) {
+                break;
+            }
+        }
+        return 0;
+    }
+};