leetcode

Daily Problem

2 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/ Problems/0629.cpp b/ Problems/0629.cpp

@@ -0,0 +1,38 @@

class Solution {

static const int MOD = 1E9 + 7;

public:

int kInversePairs(int n, int k) {

static int dp[1001][1001];

memset(dp, 0x00, sizeof(dp));

dp[0][0] = 1;

for (int i = 1; i <= n; i++) {

for (int j = 0; j <= k; j++) {

dp[i][j] = (dp[i - 1][j] + (j > 0 ? dp[i][j - 1] : 0)) % MOD;

if (j >= i) dp[i][j] = (MOD + dp[i][j] - dp[i - 1][j - i]) % MOD;

}

}

return dp[n][k];

}

};

// Space optimized

class Solution {

static const int MOD = 1E9 + 7;

public:

int kInversePairs(int n, int k) {

static int dp[2][1001];

memset(dp, 0x00, sizeof(dp));

dp[0][0] = 1;

for (int i = 1; i <= n; i++) {

for (int j = 0; j <= k; j++) {

dp[i % 2][j] = (dp[(i - 1) % 2][j] + (j > 0 ? dp[i % 2][j - 1] : 0)) % MOD;

if (j >= i) dp[i % 2][j] = (MOD + dp[i % 2][j] - dp[(i - 1) % 2][j - i]) % MOD;

}

}

return dp[n % 2][k];

}

};

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

@@ -407,6 +407,7 @@ for solving problems. | 0623 | Medium | [Add One Row to Tree](Problems/0623.cpp) | | 0626 | Medium | [Exchange Seats](Problems/0626.cpp) | | 0627 | Easy | [Swap Salary](Problems/0627.cpp) |

| 0629 | Hard | [K Inverse Pairs Array](Problems/0629.cpp) |

| 0636 | Medium | [Exclusive Time of Functions](Problems/0636.cpp) | | 0637 | Easy | [Average of Levels in Binary Tree](Problems/0637.cpp) | | 0641 | Medium | [Design Circular Deque](Problems/0641.cpp) |