Minimum Operations to Convert Number LeetCode solution in C++

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class Solution {
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 public:
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  int minimumOperations(vector<int> &nums, int start, int goal) {
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    int n = nums.size();
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    // BFS
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    queue<int> q;
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    vector<bool> vis(1001, false);
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    q.push(goal);
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    if (0 <= goal && goal <= 1000) vis[goal] = true;
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    int dist = -1;
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    bool done = false;
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    while (!q.empty() && !done) {
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      dist++;
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      int sz = q.size();
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      for (int i = 0; i < sz; i++) {
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        int cur = q.front();
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        q.pop();
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        if (cur == start) {
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          done = true;
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          break;
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        }
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        for (int j = 0; j < n; j++) {
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          if (0 <= cur - nums[j] && cur - nums[j] <= 1000 && !vis[cur - nums[j]]) {
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            q.push(cur - nums[j]);
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            vis[cur - nums[j]] = true;
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          }
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          if (0 <= cur + nums[j] && cur + nums[j] <= 1000 && !vis[cur + nums[j]]) {
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            q.push(cur + nums[j]);
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            vis[cur + nums[j]] = true;
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          }
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          if (0 <= (cur ^ nums[j]) && (cur ^ nums[j]) <= 1000 && !vis[cur ^ nums[j]]) {
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            q.push(cur ^ nums[j]);
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            vis[cur ^ nums[j]] = true;
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          }
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        }
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      }
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    }
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    return done ? dist : -1;
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  }
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};