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Hash #9

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TomaChen513 opened this issue Oct 12, 2022 · 1 comment

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TomaChen513 commented Oct 12, 2022

三数之和和四数之和太难辣

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xavier-hou commented Oct 16, 2022

@TomaChen513 @CarlChenXueYi
发现了，两种思路

排序+双指针；关键点是后面的循环如何写，如三数和

third := xxx
for second:=first+1;second<third;second++ {
    for second<third; 判断值是否不等 {
        third--
    }
    if second == third {
        break // 这个很关键，不然会有问题   
    }
    // 判断值是否等
}

分而治之，8分成4，4分成2
四数之和就可以利用这种思路，先两个二重循环，将4个数组合并成2个数组，然后2数之和

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