leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE |
commit2d501e2544eeca0f90d63eb6cb1afd4dfeb28b84
parent1b9cdc1a4c8e9064db9f94025e15af2d2d669482
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateSun, 21 May 2023 06:46:35 +0200

Daily Problem

Diffstat:
AProblems/0934.cpp|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 59 insertions(+), 0 deletions(-)

diff --git a/Problems/0934.cpp b/Problems/0934.cpp

@@ -0,0 +1,58 @@

class Solution {
static const constexpr int offs_x[] = {1, 0, -1, 0};
static const constexpr int offs_y[] = {0, 1, 0, -1};
int n;
bool valid(int i, int j) { return i >= 0 && i < n && j >= 0 && j < n; }
public:
int shortestBridge(vector<vector<int>> &grid) {
queue<pair<int, int>> dq1, dq2;
n = grid.size();
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (!grid[i][j]) continue;
dq1.push({i, j});
grid[i][j] = 2;
goto parse;
}
}
return -1;
parse:
while (!dq1.empty()) {
auto [i, j] = dq1.front();
dq1.pop();
for (int k = 0; k < 4; k++) {
int a = i + offs_x[k], b = j + offs_y[k];
if (!valid(a, b)) continue;
if (grid[a][b] == 1)
dq1.push({a, b});
else if (grid[a][b] == 0)
dq2.push({a, b});
grid[a][b] = 2;
}
}
for (int lvl = 1; !dq2.empty(); lvl++) {
for (int k = dq2.size(); k > 0; k--) {
auto [i, j] = dq2.front();
dq2.pop();
for (int k = 0; k < 4; k++) {
int a = i + offs_x[k], b = j + offs_y[k];
if (!valid(a, b)) continue;
if (grid[a][b] == 1)
return lvl;
else if (grid[a][b] == 0)
dq2.push({a, b});
grid[a][b] = 2;
}
}
}
return -1;
}
};

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

@@ -367,6 +367,7 @@ for solving problems.

| 0926 | Medium | [Flip String to Monotone Increasing](Problems/0926.cpp) |
| 0931 | Medium | [Minimum Falling Path Sum](Problems/0931.cpp) |
| 0933 | Easy | [Number of Recent Calls](Problems/0933.cpp) |
| 0934 | Medium | [Shortest Bridge](Problems/0934.cpp) |
| 0938 | Easy | [Range Sum of BST](Problems/0938.cpp) |
| 0941 | Easy | [Valid Mountain Array](Problems/0941.cpp) |
| 0944 | Easy | [Delete Columns to Make Sorted](Problems/0944.cpp) |