21 lines
427 B
JavaScript
21 lines
427 B
JavaScript
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const midpointSum = arr => {
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const sums = [];
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let sum = 0;
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sums[-1] = 0;
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for (let i = 0; i < arr.length; ++i) {
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sums[i] = arr[i] + sums[i-1];
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sum += arr[i];
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}
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for (let i = 1; i < arr.length - 1; ++i) {
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if (sums[i-1] === sum - sums[i]) {
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return i;
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}
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}
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return null;
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};
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midpointSum([-10,3,7,8,-6,-13,21]);
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midpointSum([0,0,4,0]);
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midpointSum([9,0,1,2,3,4]);
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midpointSum([4, 1, 7, 9, 3, 9]); |