leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE |
commit6919fb5e22d4a209a865b67c021d8a90497fd499
parente122f6413731e67a59aeb2f0d858b1825fd21376
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateSun, 15 Oct 2023 23:06:52 +0000

Daily Problem

Diffstat:
AProblems/1269.cpp|+++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/Problems/1269.cpp b/Problems/1269.cpp

@@ -0,0 +1,43 @@

// Top-down DP
class Solution {
static const int MOD = 1E9 + 7;
int dp[501][501];
public:
Solution() { memset(dp, 0xFF, sizeof(dp)); }
int numWays(const int steps, const int arrLen, const int crnt = 0) {
if (steps == 0) return crnt == 0;
if (dp[crnt][steps] != -1) return dp[crnt][steps];
int res = numWays(steps - 1, arrLen, crnt);
if (crnt > 0) res = (res + numWays(steps - 1, arrLen, crnt - 1)) % MOD;
if (crnt < arrLen - 1) res = (res + numWays(steps - 1, arrLen, crnt + 1)) % MOD;
return dp[crnt][steps] = res;
}
};
// Space optimized, bottom-up DP
class Solution {
static const int MOD = 1E9 + 7;
static int dp[501], pdp[501];
public:
int numWays(const int steps, int arrLen) {
memset(pdp, 0x00, sizeof(pdp));
arrLen = min(arrLen, steps), pdp[0] = 1;
for (int remain = 1; remain <= steps; remain++) {
for (int crnt = arrLen - 1; crnt >= 0; crnt--) {
int res = pdp[crnt];
if (crnt > 0) res = (res + pdp[crnt - 1]) % MOD;
if (crnt < arrLen - 1) res = (res + pdp[crnt + 1]) % MOD;
dp[crnt] = res;
}
swap(dp, pdp);
}
return pdp[0];
}
};
int Solution::dp[501];
int Solution::pdp[501];

diff --git a/README.md b/README.md

@@ -552,6 +552,7 @@ for solving problems.

| 1254 | Medium | [Number of Closed Islands](Problems/1254.cpp) |
| 1261 | Medium | [Find Elements in a Contaminated Binary Tree](Problems/1261.cpp) |
| 1268 | Medium | [Search Suggestions System](Problems/1268.cpp) |
| 1269 | Hard | [Number of Ways to Stay in the Same Place After Some Steps](Problems/1269.cpp) |
| 1277 | Medium | [Count Square Submatrices with All Ones](Problems/1277.cpp) |
| 1282 | Medium | [Group the People Given the Group Size They Belong To](Problems/1282.cpp) |
| 1286 | Medium | [Iterator for Combination](Problems/1286.cpp) |