41 lines
900 B
Java
41 lines
900 B
Java
/**
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* Forward declaration of guess API.
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*
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* @param num your guess
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* @return -1 if num is higher than the picked number 1 if num is lower than the picked number
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* otherwise return 0 int guess(int num);
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*/
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class Solution extends GuessGame {
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private enum Response {
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Smaller(-1),
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Exact(0),
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Bigger(1);
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public final int value;
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private Response(int value) {
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this.value = value;
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}
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}
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public int guessNumber(int n) {
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int lower = 1;
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int upper = n;
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while (true) {
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var mid = lower + (upper - lower) / 2;
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int response = guess(mid);
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if (response == Response.Exact.value) {
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return mid;
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} else if (response == Response.Smaller.value) {
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upper = mid - 1;
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} else if (response == Response.Bigger.value) {
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lower = mid + 1;
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} else {
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// invalid response
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return -1;
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}
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}
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}
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}
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