Number of Laser Beams in a Bank LeetCode solution in C++

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class Solution {
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 public:
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  int numberOfBeams(vector<string> &bank) {
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    int rowLaserCount = 0, totalLaserCount = 0, prevCount = 0;
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    for (int i = 0; i < bank.size(); i++) {
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      rowLaserCount = 0;
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      for (char j : bank[i]) {
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        if (j == '1') rowLaserCount++;
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      }
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      totalLaserCount += (prevCount * rowLaserCount);
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      if (rowLaserCount) prevCount = rowLaserCount;
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    }
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    return totalLaserCount;
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  }
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};